diff --git a/gstreamer-audio/src/audio_channel_position.rs b/gstreamer-audio/src/audio_channel_position.rs
index 27ac41f7c..9082de570 100644
--- a/gstreamer-audio/src/audio_channel_position.rs
+++ b/gstreamer-audio/src/audio_channel_position.rs
@@ -27,6 +27,8 @@ impl AudioChannelPosition {
     }
 
     pub fn positions_to_mask(positions: &[AudioChannelPosition], force_order: bool) -> Option<u64> {
+        assert_initialized_main_thread!();
+
         let len = positions.len();
         if len > 64 {
             return None;
@@ -59,6 +61,8 @@ impl AudioChannelPosition {
         mask: u64,
         positions: &mut [AudioChannelPosition],
     ) -> Result<(), glib::BoolError> {
+        assert_initialized_main_thread!();
+
         if positions.len() > 64 {
             return Err(glib::BoolError("Invalid number of channels"));
         }
@@ -89,6 +93,8 @@ impl AudioChannelPosition {
     pub fn positions_to_valid_order(
         positions: &mut [AudioChannelPosition],
     ) -> Result<(), glib::BoolError> {
+        assert_initialized_main_thread!();
+
         if positions.len() > 64 {
             return Err(glib::BoolError("Invalid number of channels"));
         }
@@ -121,6 +127,8 @@ impl AudioChannelPosition {
     }
 
     pub fn get_fallback_mask(channels: u32) -> u64 {
+        assert_initialized_main_thread!();
+
         unsafe { ffi::gst_audio_channel_get_fallback_mask(channels as i32) }
     }
 
@@ -128,6 +136,8 @@ impl AudioChannelPosition {
         positions: &[::AudioChannelPosition],
         force_order: bool,
     ) -> bool {
+        assert_initialized_main_thread!();
+
         if positions.len() > 64 {
             return false;
         }
@@ -157,6 +167,8 @@ pub fn buffer_reorder_channels(
     from: &[AudioChannelPosition],
     to: &[AudioChannelPosition],
 ) -> Result<(), glib::BoolError> {
+    assert_initialized_main_thread!();
+
     if from.len() != to.len() || from.len() > 64 {
         return Err(glib::BoolError("Invalid number of channels"));
     }
@@ -202,6 +214,8 @@ pub fn reorder_channels(
     from: &[AudioChannelPosition],
     to: &[AudioChannelPosition],
 ) -> Result<(), glib::BoolError> {
+    assert_initialized_main_thread!();
+
     if from.len() != to.len() || from.len() > 64 {
         return Err(glib::BoolError("Invalid number of channels"));
     }
@@ -246,6 +260,8 @@ pub fn get_channel_reorder_map(
     to: &[AudioChannelPosition],
     reorder_map: &mut [usize],
 ) -> Result<(), glib::BoolError> {
+    assert_initialized_main_thread!();
+
     if from.len() != to.len() || from.len() != reorder_map.len() || from.len() > 64 {
         return Err(glib::BoolError("Invalid number of channels"));
     }
diff --git a/gstreamer-audio/src/audio_format.rs b/gstreamer-audio/src/audio_format.rs
index 5521d7828..7702030d9 100644
--- a/gstreamer-audio/src/audio_format.rs
+++ b/gstreamer-audio/src/audio_format.rs
@@ -21,6 +21,8 @@ impl ::AudioFormat {
         width: i32,
         depth: i32,
     ) -> ::AudioFormat {
+        assert_initialized_main_thread!();
+
         unsafe {
             from_glib(ffi::gst_audio_format_build_integer(
                 sign.to_glib(),
@@ -32,6 +34,8 @@ impl ::AudioFormat {
     }
 
     pub fn from_string(s: &str) -> ::AudioFormat {
+        assert_initialized_main_thread!();
+
         unsafe { from_glib(ffi::gst_audio_format_from_string(s.to_glib_none().0)) }
     }
 
@@ -48,6 +52,8 @@ impl str::FromStr for ::AudioFormat {
     type Err = ();
 
     fn from_str(s: &str) -> Result<Self, ()> {
+        skip_assert_initialized!();
+
         let format = Self::from_string(s);
         if format == ::AudioFormat::Unknown {
             Err(())
diff --git a/gstreamer-audio/src/audio_format_info.rs b/gstreamer-audio/src/audio_format_info.rs
index 7c84b8ea9..fd47a4e07 100644
--- a/gstreamer-audio/src/audio_format_info.rs
+++ b/gstreamer-audio/src/audio_format_info.rs
@@ -26,6 +26,8 @@ pub enum AudioEndianness {
 
 impl FromGlib<i32> for AudioEndianness {
     fn from_glib(value: i32) -> Self {
+        assert_initialized_main_thread!();
+
         match value {
             1234 => AudioEndianness::LittleEndian,
             4321 => AudioEndianness::BigEndian,
@@ -50,6 +52,8 @@ pub struct AudioFormatInfo(&'static ffi::GstAudioFormatInfo);
 
 impl AudioFormatInfo {
     pub fn from_format(format: ::AudioFormat) -> AudioFormatInfo {
+        assert_initialized_main_thread!();
+
         unsafe {
             let info = ffi::gst_audio_format_get_info(format.to_glib());
             assert!(!info.is_null());
@@ -227,6 +231,7 @@ impl str::FromStr for ::AudioFormatInfo {
     type Err = ();
 
     fn from_str(s: &str) -> Result<Self, ()> {
+        skip_assert_initialized!();
         let format = s.parse()?;
         Ok(AudioFormatInfo::from_format(format))
     }
@@ -234,6 +239,7 @@ impl str::FromStr for ::AudioFormatInfo {
 
 impl From<::AudioFormat> for AudioFormatInfo {
     fn from(f: ::AudioFormat) -> Self {
+        skip_assert_initialized!();
         Self::from_format(f)
     }
 }
diff --git a/gstreamer-audio/src/audio_info.rs b/gstreamer-audio/src/audio_info.rs
index 881bd0aee..0fb33dde5 100644
--- a/gstreamer-audio/src/audio_info.rs
+++ b/gstreamer-audio/src/audio_info.rs
@@ -117,6 +117,8 @@ impl<'a> AudioInfoBuilder<'a> {
 
 impl AudioInfo {
     pub fn new<'a>(format: ::AudioFormat, rate: u32, channels: u32) -> AudioInfoBuilder<'a> {
+        assert_initialized_main_thread!();
+
         AudioInfoBuilder {
             format: format,
             rate: rate,
@@ -128,6 +130,8 @@ impl AudioInfo {
     }
 
     pub fn from_caps(caps: &gst::Caps) -> Option<Self> {
+        skip_assert_initialized!();
+
         unsafe {
             let mut info = mem::uninitialized();
             if from_glib(ffi::gst_audio_info_from_caps(&mut info, caps.as_ptr())) {
@@ -156,6 +160,8 @@ impl AudioInfo {
         src_val: i64,
         dest_fmt: gst::Format,
     ) -> Option<i64> {
+        assert_initialized_main_thread!();
+
         unsafe {
             let mut dest_val = mem::uninitialized();
             if from_glib(ffi::gst_audio_info_convert(
diff --git a/gstreamer-audio/src/lib.rs b/gstreamer-audio/src/lib.rs
index 9c56d2ce0..ae4a5152e 100644
--- a/gstreamer-audio/src/lib.rs
+++ b/gstreamer-audio/src/lib.rs
@@ -21,8 +21,9 @@ extern crate glib;
 
 macro_rules! assert_initialized_main_thread {
     () => (
-        use gst_ffi;
-        assert_eq!(unsafe {gst_ffi::gst_is_initialized()}, ::glib_ffi::GTRUE)
+        if unsafe {::gst_ffi::gst_is_initialized()} != ::glib_ffi::GTRUE {
+            panic!("GStreamer has not been initialized. Call `gst::init` first.");
+        }
     )
 }
 
@@ -56,6 +57,8 @@ pub fn audio_buffer_clip(
     rate: u32,
     channels: u32,
 ) -> gst::Buffer {
+    skip_assert_initialized!();
+
     unsafe {
         from_glib_full(ffi::gst_audio_buffer_clip(
             buffer.into_ptr(),
diff --git a/gstreamer-video/src/video_frame.rs b/gstreamer-video/src/video_frame.rs
index aaa0fb8e2..3d6f9de88 100644
--- a/gstreamer-video/src/video_frame.rs
+++ b/gstreamer-video/src/video_frame.rs
@@ -179,7 +179,7 @@ impl VideoFrame<Readable> {
         buffer: gst::Buffer,
         info: &::VideoInfo,
     ) -> Result<VideoFrame<Readable>, gst::Buffer> {
-        assert_initialized_main_thread!();
+        skip_assert_initialized!();
 
         unsafe {
             let mut frame = mem::zeroed();
@@ -206,7 +206,7 @@ impl VideoFrame<Readable> {
         id: i32,
         info: &::VideoInfo,
     ) -> Result<VideoFrame<Readable>, gst::Buffer> {
-        assert_initialized_main_thread!();
+        skip_assert_initialized!();
 
         unsafe {
             let mut frame = mem::zeroed();
@@ -239,7 +239,7 @@ impl VideoFrame<Writable> {
         buffer: gst::Buffer,
         info: &::VideoInfo,
     ) -> Result<VideoFrame<Writable>, gst::Buffer> {
-        assert_initialized_main_thread!();
+        skip_assert_initialized!();
 
         unsafe {
             let mut frame = mem::zeroed();
@@ -267,7 +267,7 @@ impl VideoFrame<Writable> {
         id: i32,
         info: &::VideoInfo,
     ) -> Result<VideoFrame<Writable>, gst::Buffer> {
-        assert_initialized_main_thread!();
+        skip_assert_initialized!();
 
         unsafe {
             let mut frame = mem::zeroed();
diff --git a/gstreamer-video/src/video_info.rs b/gstreamer-video/src/video_info.rs
index c3534738c..8837c74c5 100644
--- a/gstreamer-video/src/video_info.rs
+++ b/gstreamer-video/src/video_info.rs
@@ -420,7 +420,7 @@ impl VideoInfo {
     }
 
     pub fn from_caps(caps: &gst::Caps) -> Option<Self> {
-        assert_initialized_main_thread!();
+        skip_assert_initialized!();
 
         unsafe {
             let mut info = mem::uninitialized();
diff --git a/gstreamer/src/buffer.rs b/gstreamer/src/buffer.rs
index a758b443e..b6fd6b642 100644
--- a/gstreamer/src/buffer.rs
+++ b/gstreamer/src/buffer.rs
@@ -54,6 +54,8 @@ impl GstRc<BufferRef> {
     }
 
     pub fn with_size(size: usize) -> Option<Self> {
+        assert_initialized_main_thread!();
+
         let raw = unsafe { ffi::gst_buffer_new_allocate(ptr::null_mut(), size, ptr::null_mut()) };
         if raw.is_null() {
             None
@@ -68,6 +70,8 @@ impl GstRc<BufferRef> {
     }
 
     pub fn from_vec(vec: Vec<u8>) -> Option<Self> {
+        assert_initialized_main_thread!();
+
         let raw = unsafe {
             let mut vec = Box::new(vec);
             let maxsize = vec.capacity();
@@ -133,6 +137,7 @@ impl GstRc<BufferRef> {
     }
 
     pub fn append(buffer: Self, other: Self) -> Self {
+        skip_assert_initialized!();
         unsafe { from_glib_full(ffi::gst_buffer_append(buffer.into_ptr(), other.into_ptr())) }
     }
 }
diff --git a/gstreamer/src/bufferlist.rs b/gstreamer/src/bufferlist.rs
index e30a91688..c7c21f87e 100644
--- a/gstreamer/src/bufferlist.rs
+++ b/gstreamer/src/bufferlist.rs
@@ -101,6 +101,7 @@ pub struct Iter<'a> {
 
 impl<'a> Iter<'a> {
     fn new(list: &'a BufferListRef) -> Iter<'a> {
+        skip_assert_initialized!();
         Iter {
             list: list,
             idx: 0,
diff --git a/gstreamer/src/bus.rs b/gstreamer/src/bus.rs
index cc1fd64dc..e6d7df2fe 100644
--- a/gstreamer/src/bus.rs
+++ b/gstreamer/src/bus.rs
@@ -87,6 +87,7 @@ impl Bus {
     where
         F: FnMut(&Bus, &Message) -> Continue + Send + 'static,
     {
+        skip_assert_initialized!();
         unsafe {
             let source = ffi::gst_bus_create_watch(self.to_glib_none().0);
             let trampoline = trampoline_watch as gpointer;
@@ -147,6 +148,7 @@ pub struct BusStream(Bus, Arc<Mutex<Option<Task>>>);
 #[cfg(feature = "futures")]
 impl BusStream {
     pub fn new(bus: &Bus) -> Self {
+        skip_assert_initialized!();
         let task = Arc::new(Mutex::new(None));
         let task_clone = task.clone();
 
diff --git a/gstreamer/src/caps.rs b/gstreamer/src/caps.rs
index 3cbe26752..aca3defde 100644
--- a/gstreamer/src/caps.rs
+++ b/gstreamer/src/caps.rs
@@ -62,14 +62,17 @@ impl GstRc<CapsRef> {
     }
 
     pub fn fixate(caps: Self) -> Self {
+        skip_assert_initialized!();
         unsafe { from_glib_full(ffi::gst_caps_fixate(caps.into_ptr())) }
     }
 
     pub fn merge(caps: Self, other: Self) -> Self {
+        skip_assert_initialized!();
         unsafe { from_glib_full(ffi::gst_caps_merge(caps.into_ptr(), other.into_ptr())) }
     }
 
     pub fn merge_structure(caps: Self, other: Structure) -> Self {
+        skip_assert_initialized!();
         unsafe {
             from_glib_full(ffi::gst_caps_merge_structure(
                 caps.into_ptr(),
@@ -79,18 +82,22 @@ impl GstRc<CapsRef> {
     }
 
     pub fn normalize(caps: Self) -> Self {
+        skip_assert_initialized!();
         unsafe { from_glib_full(ffi::gst_caps_normalize(caps.into_ptr())) }
     }
 
     pub fn simplify(caps: Self) -> Self {
+        skip_assert_initialized!();
         unsafe { from_glib_full(ffi::gst_caps_simplify(caps.into_ptr())) }
     }
 
     pub fn subtract(caps: Self, other: Self) -> Self {
+        skip_assert_initialized!();
         unsafe { from_glib_full(ffi::gst_caps_subtract(caps.into_ptr(), other.into_ptr())) }
     }
 
     pub fn truncate(caps: Self) -> Self {
+        skip_assert_initialized!();
         unsafe { from_glib_full(ffi::gst_caps_truncate(caps.into_ptr())) }
     }
 }
@@ -99,6 +106,7 @@ impl str::FromStr for Caps {
     type Err = ();
 
     fn from_str(s: &str) -> Result<Self, ()> {
+        skip_assert_initialized!();
         Caps::from_string(s).ok_or(())
     }
 }
@@ -251,80 +259,80 @@ impl glib::types::StaticType for CapsRef {
 
 macro_rules! define_iter(
     ($name:ident, $typ:ty, $styp:ty) => {
+    pub struct $name<'a> {
+        caps: $typ,
+        idx: u32,
+        n_structures: u32,
+    }
 
-pub struct $name<'a> {
-    caps: $typ,
-    idx: u32,
-    n_structures: u32,
-}
+    impl<'a> $name<'a> {
+        fn new(caps: $typ) -> $name<'a> {
+            skip_assert_initialized!();
+            let n_structures = caps.get_size();
 
-impl<'a> $name<'a> {
-    pub fn new(caps: $typ) -> $name<'a> {
-        let n_structures = caps.get_size();
-
-        $name {
-            caps: caps,
-            idx: 0,
-            n_structures: n_structures,
+            $name {
+                caps: caps,
+                idx: 0,
+                n_structures: n_structures,
+            }
         }
     }
-}
 
-impl<'a> Iterator for $name<'a> {
-    type Item = $styp;
+    impl<'a> Iterator for $name<'a> {
+        type Item = $styp;
 
-    fn next(&mut self) -> Option<Self::Item> {
-        if self.idx >= self.n_structures {
-            return None;
-        }
-
-        unsafe {
-            let structure = ffi::gst_caps_get_structure(self.caps.as_ptr(), self.idx);
-            if structure.is_null() {
+        fn next(&mut self) -> Option<Self::Item> {
+            if self.idx >= self.n_structures {
                 return None;
             }
 
-            self.idx += 1;
-            Some(StructureRef::from_glib_borrow_mut(
-                structure as *mut ffi::GstStructure,
-            ))
+            unsafe {
+                let structure = ffi::gst_caps_get_structure(self.caps.as_ptr(), self.idx);
+                if structure.is_null() {
+                    return None;
+                }
+
+                self.idx += 1;
+                Some(StructureRef::from_glib_borrow_mut(
+                    structure as *mut ffi::GstStructure,
+                ))
+            }
+        }
+
+        fn size_hint(&self) -> (usize, Option<usize>) {
+            if self.idx == self.n_structures {
+                return (0, Some(0));
+            }
+
+            let remaining = (self.n_structures - self.idx) as usize;
+
+            (remaining, Some(remaining))
         }
     }
 
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        if self.idx == self.n_structures {
-            return (0, Some(0));
-        }
-
-        let remaining = (self.n_structures - self.idx) as usize;
-
-        (remaining, Some(remaining))
-    }
-}
-
-impl<'a> DoubleEndedIterator for $name<'a> {
-    fn next_back(&mut self) -> Option<Self::Item> {
-        if self.idx == self.n_structures {
-            return None;
-        }
-
-        self.n_structures -= 1;
-
-        unsafe {
-            let structure = ffi::gst_caps_get_structure(self.caps.as_ptr(), self.n_structures);
-            if structure.is_null() {
+    impl<'a> DoubleEndedIterator for $name<'a> {
+        fn next_back(&mut self) -> Option<Self::Item> {
+            if self.idx == self.n_structures {
                 return None;
             }
 
-            Some(StructureRef::from_glib_borrow_mut(
-                structure as *mut ffi::GstStructure,
-            ))
+            self.n_structures -= 1;
+
+            unsafe {
+                let structure = ffi::gst_caps_get_structure(self.caps.as_ptr(), self.n_structures);
+                if structure.is_null() {
+                    return None;
+                }
+
+                Some(StructureRef::from_glib_borrow_mut(
+                    structure as *mut ffi::GstStructure,
+                ))
+            }
         }
     }
-}
 
-impl<'a> ExactSizeIterator for $name<'a> {}
-}
+    impl<'a> ExactSizeIterator for $name<'a> {}
+    }
 );
 
 define_iter!(Iter, &'a CapsRef, &'a StructureRef);
diff --git a/gstreamer/src/clock.rs b/gstreamer/src/clock.rs
index d37448809..08e597c0e 100644
--- a/gstreamer/src/clock.rs
+++ b/gstreamer/src/clock.rs
@@ -152,6 +152,7 @@ impl<O: IsA<Clock> + IsA<glib::object::Object>> ClockExtManual for O {
         start_time: ClockTime,
         interval: ClockTime,
     ) -> Result<(), glib::BoolError> {
+        skip_assert_initialized!();
         unsafe {
             let res: bool = from_glib(ffi::gst_clock_periodic_id_reinit(
                 self.to_glib_none().0,
diff --git a/gstreamer/src/element.rs b/gstreamer/src/element.rs
index 7bd8d554e..154795872 100644
--- a/gstreamer/src/element.rs
+++ b/gstreamer/src/element.rs
@@ -23,6 +23,7 @@ use gobject_ffi;
 
 impl Element {
     pub fn link_many<E: IsA<Element>>(elements: &[&E]) -> Result<(), glib::BoolError> {
+        skip_assert_initialized!();
         for (e1, e2) in elements.iter().zip(elements.iter().skip(1)) {
             unsafe {
                 let ret: bool = from_glib(ffi::gst_element_link(
@@ -39,6 +40,7 @@ impl Element {
     }
 
     pub fn unlink_many<E: IsA<Element>>(elements: &[&E]) {
+        skip_assert_initialized!();
         for (e1, e2) in elements.iter().zip(elements.iter().skip(1)) {
             unsafe {
                 ffi::gst_element_unlink(e1.to_glib_none().0, e2.to_glib_none().0);
diff --git a/gstreamer/src/event.rs b/gstreamer/src/event.rs
index c949f54c6..93d6529aa 100644
--- a/gstreamer/src/event.rs
+++ b/gstreamer/src/event.rs
@@ -135,22 +135,27 @@ impl EventRef {
 
 impl Event {
     pub fn new_flush_start() -> FlushStartBuilder {
+        assert_initialized_main_thread!();
         FlushStartBuilder::new()
     }
 
     pub fn new_flush_stop(reset_time: bool) -> FlushStopBuilder {
+        assert_initialized_main_thread!();
         FlushStopBuilder::new(reset_time)
     }
 
     pub fn new_stream_start(stream_id: &str) -> StreamStartBuilder {
+        assert_initialized_main_thread!();
         StreamStartBuilder::new(stream_id)
     }
 
     pub fn new_caps(caps: &::Caps) -> CapsBuilder {
+        assert_initialized_main_thread!();
         CapsBuilder::new(caps)
     }
 
     pub fn new_segment(segment: &::Segment) -> SegmentBuilder {
+        assert_initialized_main_thread!();
         SegmentBuilder::new(segment)
     }
 
@@ -158,10 +163,12 @@ impl Event {
     pub fn new_stream_collection(
         stream_collection: &::StreamCollection,
     ) -> StreamCollectionBuilder {
+        assert_initialized_main_thread!();
         StreamCollectionBuilder::new(stream_collection)
     }
 
     pub fn new_tag(tags: ::TagList) -> TagBuilder {
+        assert_initialized_main_thread!();
         TagBuilder::new(tags)
     }
 
@@ -171,23 +178,28 @@ impl Event {
         maxsize: i64,
         async: bool,
     ) -> BufferSizeBuilder {
+        assert_initialized_main_thread!();
         BufferSizeBuilder::new(format, minsize, maxsize, async)
     }
 
     pub fn new_sink_message<'a>(name: &'a str, msg: &'a ::Message) -> SinkMessageBuilder<'a> {
+        assert_initialized_main_thread!();
         SinkMessageBuilder::new(name, msg)
     }
 
     #[cfg(feature = "v1_10")]
     pub fn new_stream_group_done(group_id: u32) -> StreamGroupDoneBuilder {
+        assert_initialized_main_thread!();
         StreamGroupDoneBuilder::new(group_id)
     }
 
     pub fn new_eos() -> EosBuilder {
+        assert_initialized_main_thread!();
         EosBuilder::new()
     }
 
     pub fn new_toc(toc: &::Toc, updated: bool) -> TocBuilder {
+        assert_initialized_main_thread!();
         TocBuilder::new(toc, updated)
     }
 
@@ -196,18 +208,22 @@ impl Event {
         data: &'a ::Buffer,
         origin: &'a str,
     ) -> ProtectionBuilder<'a> {
+        assert_initialized_main_thread!();
         ProtectionBuilder::new(system_id, data, origin)
     }
 
     pub fn new_segment_done(format: ::Format, position: i64) -> SegmentDoneBuilder {
+        assert_initialized_main_thread!();
         SegmentDoneBuilder::new(format, position)
     }
 
     pub fn new_gap(timestamp: u64, duration: u64) -> GapBuilder {
+        assert_initialized_main_thread!();
         GapBuilder::new(timestamp, duration)
     }
 
     pub fn new_qos(type_: ::QOSType, proportion: f64, diff: i64, timestamp: u64) -> QosBuilder {
+        assert_initialized_main_thread!();
         QosBuilder::new(type_, proportion, diff, timestamp)
     }
 
@@ -220,14 +236,17 @@ impl Event {
         stop_type: ::SeekType,
         stop: i64,
     ) -> SeekBuilder {
+        assert_initialized_main_thread!();
         SeekBuilder::new(rate, format, flags, start_type, start, stop_type, stop)
     }
 
     pub fn new_navigation(structure: ::Structure) -> NavigationBuilder {
+        assert_initialized_main_thread!();
         NavigationBuilder::new(structure)
     }
 
     pub fn new_latency(latency: u64) -> LatencyBuilder {
+        assert_initialized_main_thread!();
         LatencyBuilder::new(latency)
     }
 
@@ -238,43 +257,53 @@ impl Event {
         flush: bool,
         intermediate: bool,
     ) -> StepBuilder {
+        assert_initialized_main_thread!();
         StepBuilder::new(format, amount, rate, flush, intermediate)
     }
 
     pub fn new_reconfigure() -> ReconfigureBuilder {
+        assert_initialized_main_thread!();
         ReconfigureBuilder::new()
     }
 
     pub fn new_toc_select(uid: &str) -> TocSelectBuilder {
+        assert_initialized_main_thread!();
         TocSelectBuilder::new(uid)
     }
 
     #[cfg(feature = "v1_10")]
     pub fn new_select_streams<'a>(streams: &'a [&'a str]) -> SelectStreamsBuilder<'a> {
+        assert_initialized_main_thread!();
         SelectStreamsBuilder::new(streams)
     }
 
     pub fn new_custom_upstream(structure: ::Structure) -> CustomUpstreamBuilder {
+        assert_initialized_main_thread!();
         CustomUpstreamBuilder::new(structure)
     }
 
     pub fn new_custom_downstream(structure: ::Structure) -> CustomDownstreamBuilder {
+        assert_initialized_main_thread!();
         CustomDownstreamBuilder::new(structure)
     }
 
     pub fn new_custom_downstream_oob(structure: ::Structure) -> CustomDownstreamOobBuilder {
+        assert_initialized_main_thread!();
         CustomDownstreamOobBuilder::new(structure)
     }
 
     pub fn new_custom_downstream_sticky(structure: ::Structure) -> CustomDownstreamStickyBuilder {
+        assert_initialized_main_thread!();
         CustomDownstreamStickyBuilder::new(structure)
     }
 
     pub fn new_custom_both(structure: ::Structure) -> CustomBothBuilder {
+        assert_initialized_main_thread!();
         CustomBothBuilder::new(structure)
     }
 
     pub fn new_custom_both_oob(structure: ::Structure) -> CustomBothOobBuilder {
+        assert_initialized_main_thread!();
         CustomBothOobBuilder::new(structure)
     }
 }
@@ -712,7 +741,8 @@ pub struct FlushStartBuilder {
     running_time_offset: Option<i64>,
 }
 impl FlushStartBuilder {
-    pub fn new() -> Self {
+    fn new() -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -728,7 +758,8 @@ pub struct FlushStopBuilder {
     reset_time: bool,
 }
 impl FlushStopBuilder {
-    pub fn new(reset_time: bool) -> Self {
+    fn new(reset_time: bool) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -749,7 +780,8 @@ pub struct StreamStartBuilder<'a> {
     group_id: Option<u32>,
 }
 impl<'a> StreamStartBuilder<'a> {
-    pub fn new(stream_id: &'a str) -> Self {
+    fn new(stream_id: &'a str) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -791,7 +823,8 @@ pub struct CapsBuilder<'a> {
     caps: &'a ::Caps,
 }
 impl<'a> CapsBuilder<'a> {
-    pub fn new(caps: &'a ::Caps) -> Self {
+    fn new(caps: &'a ::Caps) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -808,7 +841,8 @@ pub struct SegmentBuilder<'a> {
     segment: &'a ::Segment,
 }
 impl<'a> SegmentBuilder<'a> {
-    pub fn new(segment: &'a ::Segment) -> Self {
+    fn new(segment: &'a ::Segment) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -829,7 +863,8 @@ pub struct StreamCollectionBuilder<'a> {
 }
 #[cfg(feature = "v1_10")]
 impl<'a> StreamCollectionBuilder<'a> {
-    pub fn new(stream_collection: &'a ::StreamCollection) -> Self {
+    fn new(stream_collection: &'a ::StreamCollection) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -848,7 +883,8 @@ pub struct TagBuilder {
     tags: Option<::TagList>,
 }
 impl TagBuilder {
-    pub fn new(tags: ::TagList) -> Self {
+    fn new(tags: ::TagList) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -871,7 +907,8 @@ pub struct BufferSizeBuilder {
     async: bool,
 }
 impl BufferSizeBuilder {
-    pub fn new(fmt: ::Format, minsize: i64, maxsize: i64, async: bool) -> Self {
+    fn new(fmt: ::Format, minsize: i64, maxsize: i64, async: bool) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -894,7 +931,8 @@ pub struct SinkMessageBuilder<'a> {
     msg: &'a ::Message,
 }
 impl<'a> SinkMessageBuilder<'a> {
-    pub fn new(name: &'a str, msg: &'a ::Message) -> Self {
+    fn new(name: &'a str, msg: &'a ::Message) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -916,7 +954,8 @@ pub struct StreamGroupDoneBuilder {
 }
 #[cfg(feature = "v1_10")]
 impl StreamGroupDoneBuilder {
-    pub fn new(uid: u32) -> Self {
+    fn new(uid: u32) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -932,7 +971,8 @@ pub struct EosBuilder {
     running_time_offset: Option<i64>,
 }
 impl EosBuilder {
-    pub fn new() -> Self {
+    fn new() -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -949,7 +989,8 @@ pub struct TocBuilder<'a> {
     updated: bool,
 }
 impl<'a> TocBuilder<'a> {
-    pub fn new(toc: &'a ::Toc, updated: bool) -> Self {
+    fn new(toc: &'a ::Toc, updated: bool) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -971,7 +1012,8 @@ pub struct ProtectionBuilder<'a> {
     origin: &'a str,
 }
 impl<'a> ProtectionBuilder<'a> {
-    pub fn new(system_id: &'a str, data: &'a ::Buffer, origin: &'a str) -> Self {
+    fn new(system_id: &'a str, data: &'a ::Buffer, origin: &'a str) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -997,7 +1039,8 @@ pub struct SegmentDoneBuilder {
     position: i64,
 }
 impl SegmentDoneBuilder {
-    pub fn new(fmt: ::Format, position: i64) -> Self {
+    fn new(fmt: ::Format, position: i64) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -1018,7 +1061,8 @@ pub struct GapBuilder {
     duration: u64,
 }
 impl GapBuilder {
-    pub fn new(timestamp: u64, duration: u64) -> Self {
+    fn new(timestamp: u64, duration: u64) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -1039,7 +1083,8 @@ pub struct QosBuilder {
     timestamp: u64,
 }
 impl QosBuilder {
-    pub fn new(type_: ::QOSType, proportion: f64, diff: i64, timestamp: u64) -> Self {
+    fn new(type_: ::QOSType, proportion: f64, diff: i64, timestamp: u64) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -1067,7 +1112,7 @@ pub struct SeekBuilder {
     stop: i64,
 }
 impl SeekBuilder {
-    pub fn new(
+    fn new(
         rate: f64,
         fmt: ::Format,
         flags: ::SeekFlags,
@@ -1076,6 +1121,7 @@ impl SeekBuilder {
         stop_type: ::SeekType,
         stop: i64,
     ) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -1108,7 +1154,8 @@ pub struct NavigationBuilder {
     structure: Option<Structure>,
 }
 impl NavigationBuilder {
-    pub fn new(structure: Structure) -> Self {
+    fn new(structure: Structure) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -1131,7 +1178,8 @@ pub struct LatencyBuilder {
     latency: u64,
 }
 impl LatencyBuilder {
-    pub fn new(latency: u64) -> Self {
+    fn new(latency: u64) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -1152,7 +1200,8 @@ pub struct StepBuilder {
     intermediate: bool,
 }
 impl StepBuilder {
-    pub fn new(fmt: ::Format, amount: u64, rate: f64, flush: bool, intermediate: bool) -> Self {
+    fn new(fmt: ::Format, amount: u64, rate: f64, flush: bool, intermediate: bool) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -1180,7 +1229,8 @@ pub struct ReconfigureBuilder {
     running_time_offset: Option<i64>,
 }
 impl ReconfigureBuilder {
-    pub fn new() -> Self {
+    fn new() -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -1196,7 +1246,8 @@ pub struct TocSelectBuilder<'a> {
     uid: &'a str,
 }
 impl<'a> TocSelectBuilder<'a> {
-    pub fn new(uid: &'a str) -> Self {
+    fn new(uid: &'a str) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -1217,7 +1268,8 @@ pub struct SelectStreamsBuilder<'a> {
 }
 #[cfg(feature = "v1_10")]
 impl<'a> SelectStreamsBuilder<'a> {
-    pub fn new(streams: &'a [&'a str]) -> Self {
+    fn new(streams: &'a [&'a str]) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -1236,7 +1288,8 @@ pub struct CustomUpstreamBuilder {
     structure: Option<Structure>,
 }
 impl CustomUpstreamBuilder {
-    pub fn new(structure: Structure) -> Self {
+    fn new(structure: Structure) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -1260,7 +1313,8 @@ pub struct CustomDownstreamBuilder {
     structure: Option<Structure>,
 }
 impl CustomDownstreamBuilder {
-    pub fn new(structure: Structure) -> Self {
+    fn new(structure: Structure) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -1284,7 +1338,8 @@ pub struct CustomDownstreamOobBuilder {
     structure: Option<Structure>,
 }
 impl CustomDownstreamOobBuilder {
-    pub fn new(structure: Structure) -> Self {
+    fn new(structure: Structure) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -1310,7 +1365,8 @@ pub struct CustomDownstreamStickyBuilder {
     structure: Option<Structure>,
 }
 impl CustomDownstreamStickyBuilder {
-    pub fn new(structure: Structure) -> Self {
+    fn new(structure: Structure) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -1336,7 +1392,8 @@ pub struct CustomBothBuilder {
     structure: Option<Structure>,
 }
 impl CustomBothBuilder {
-    pub fn new(structure: Structure) -> Self {
+    fn new(structure: Structure) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
@@ -1359,7 +1416,8 @@ pub struct CustomBothOobBuilder {
     structure: Option<Structure>,
 }
 impl CustomBothOobBuilder {
-    pub fn new(structure: Structure) -> Self {
+    fn new(structure: Structure) -> Self {
+        skip_assert_initialized!();
         Self {
             seqnum: None,
             running_time_offset: None,
diff --git a/gstreamer/src/message.rs b/gstreamer/src/message.rs
index 407e2b364..e97b4be9a 100644
--- a/gstreamer/src/message.rs
+++ b/gstreamer/src/message.rs
@@ -129,34 +129,42 @@ impl MessageRef {
 
 impl Message {
     pub fn new_eos() -> EosBuilder {
+        assert_initialized_main_thread!();
         EosBuilder::new()
     }
 
     pub fn new_error(error: &glib::Error) -> ErrorBuilder {
+        assert_initialized_main_thread!();
         ErrorBuilder::new(error)
     }
 
     pub fn new_warning(error: &glib::Error) -> WarningBuilder {
+        assert_initialized_main_thread!();
         WarningBuilder::new(error)
     }
 
     pub fn new_info(error: &glib::Error) -> InfoBuilder {
+        assert_initialized_main_thread!();
         InfoBuilder::new(error)
     }
 
     pub fn new_tag(tags: &TagList) -> TagBuilder {
+        assert_initialized_main_thread!();
         TagBuilder::new(tags)
     }
 
     pub fn new_buffering(percent: i32) -> BufferingBuilder {
+        assert_initialized_main_thread!();
         BufferingBuilder::new(percent)
     }
 
     pub fn new_state_changed(old: ::State, new: ::State, pending: ::State) -> StateChangedBuilder {
+        assert_initialized_main_thread!();
         StateChangedBuilder::new(old, new, pending)
     }
 
     pub fn new_state_dirty() -> StateDirtyBuilder {
+        assert_initialized_main_thread!();
         StateDirtyBuilder::new()
     }
 
@@ -169,18 +177,22 @@ impl Message {
         duration: u64,
         eos: bool,
     ) -> StepDoneBuilder {
+        assert_initialized_main_thread!();
         StepDoneBuilder::new(format, amount, rate, flush, intermediate, duration, eos)
     }
 
     pub fn new_clock_provide(clock: &::Clock, ready: bool) -> ClockProvideBuilder {
+        assert_initialized_main_thread!();
         ClockProvideBuilder::new(clock, ready)
     }
 
     pub fn new_clock_lost(clock: &::Clock) -> ClockLostBuilder {
+        assert_initialized_main_thread!();
         ClockLostBuilder::new(clock)
     }
 
     pub fn new_new_clock(clock: &::Clock) -> NewClockBuilder {
+        assert_initialized_main_thread!();
         NewClockBuilder::new(clock)
     }
 
@@ -189,45 +201,60 @@ impl Message {
         owner: &::Element,
         busy: bool,
     ) -> StructureChangeBuilder {
+        assert_initialized_main_thread!();
         StructureChangeBuilder::new(type_, owner, busy)
     }
 
     pub fn new_stream_status(type_: ::StreamStatusType, owner: &::Element) -> StreamStatusBuilder {
+        assert_initialized_main_thread!();
         StreamStatusBuilder::new(type_, owner)
     }
 
     pub fn new_application(structure: ::Structure) -> ApplicationBuilder {
+        assert_initialized_main_thread!();
         ApplicationBuilder::new(structure)
     }
 
     pub fn new_element(structure: ::Structure) -> ElementBuilder {
+        assert_initialized_main_thread!();
         ElementBuilder::new(structure)
     }
 
     pub fn new_segment_start(format: ::Format, position: i64) -> SegmentStartBuilder {
+        assert_initialized_main_thread!();
         SegmentStartBuilder::new(format, position)
     }
 
     pub fn new_segment_done(format: ::Format, position: i64) -> SegmentDoneBuilder {
+        assert_initialized_main_thread!();
         SegmentDoneBuilder::new(format, position)
     }
 
     pub fn new_duration_changed() -> DurationChangedBuilder {
+        assert_initialized_main_thread!();
         DurationChangedBuilder::new()
     }
 
     pub fn new_latency() -> LatencyBuilder {
+        assert_initialized_main_thread!();
         LatencyBuilder::new()
     }
 
     pub fn new_async_start() -> AsyncStartBuilder {
+        assert_initialized_main_thread!();
         AsyncStartBuilder::new()
     }
 
     pub fn new_async_done(running_time: u64) -> AsyncDoneBuilder {
+        assert_initialized_main_thread!();
         AsyncDoneBuilder::new(running_time)
     }
 
+    pub fn new_request_state(state: ::State) -> RequestStateBuilder {
+        assert_initialized_main_thread!();
+        RequestStateBuilder::new(state)
+    }
+
     pub fn new_step_start(
         active: bool,
         format: ::Format,
@@ -236,6 +263,7 @@ impl Message {
         flush: bool,
         intermediate: bool,
     ) -> StepStartBuilder {
+        assert_initialized_main_thread!();
         StepStartBuilder::new(active, format, amount, rate, flush, intermediate)
     }
 
@@ -246,34 +274,47 @@ impl Message {
         timestamp: u64,
         duration: u64,
     ) -> QosBuilder {
+        assert_initialized_main_thread!();
         QosBuilder::new(live, running_time, stream_time, timestamp, duration)
     }
 
+    pub fn new_progress<'a>(type_: ::ProgressType) -> ProgressBuilder<'a> {
+        assert_initialized_main_thread!();
+        ProgressBuilder::new(type_)
+    }
+
     pub fn new_toc(toc: &::Toc, updated: bool) -> TocBuilder {
+        assert_initialized_main_thread!();
         TocBuilder::new(toc, updated)
     }
 
     pub fn new_reset_time(running_time: u64) -> ResetTimeBuilder {
+        assert_initialized_main_thread!();
         ResetTimeBuilder::new(running_time)
     }
 
     pub fn new_stream_start() -> StreamStartBuilder {
+        assert_initialized_main_thread!();
         StreamStartBuilder::new()
     }
 
     pub fn new_need_context(context_type: &str) -> NeedContextBuilder {
+        assert_initialized_main_thread!();
         NeedContextBuilder::new(context_type)
     }
 
     pub fn new_have_context(context: ::Context) -> HaveContextBuilder {
+        assert_initialized_main_thread!();
         HaveContextBuilder::new(context)
     }
 
     pub fn new_device_added(device: &::Device) -> DeviceAddedBuilder {
+        assert_initialized_main_thread!();
         DeviceAddedBuilder::new(device)
     }
 
     pub fn new_device_removed(device: &::Device) -> DeviceRemovedBuilder {
+        assert_initialized_main_thread!();
         DeviceRemovedBuilder::new(device)
     }
 
@@ -282,16 +323,19 @@ impl Message {
         property_name: &'a str,
         value: &'a glib::Value,
     ) -> PropertyNotifyBuilder<'a> {
+        assert_initialized_main_thread!();
         PropertyNotifyBuilder::new(property_name, value)
     }
 
     #[cfg(feature = "v1_10")]
     pub fn new_stream_collection(collection: &::StreamCollection) -> StreamCollectionBuilder {
+        assert_initialized_main_thread!();
         StreamCollectionBuilder::new(collection)
     }
 
     #[cfg(feature = "v1_10")]
     pub fn new_streams_selected(collection: &::StreamCollection) -> StreamsSelectedBuilder {
+        assert_initialized_main_thread!();
         StreamsSelectedBuilder::new(collection)
     }
 
@@ -301,6 +345,7 @@ impl Message {
         tag_list: Option<&'a TagList>,
         entry_struct: Option<Structure>,
     ) -> RedirectBuilder<'a> {
+        assert_initialized_main_thread!();
         RedirectBuilder::new(location, tag_list, entry_struct)
     }
 }
@@ -1120,7 +1165,8 @@ pub struct EosBuilder {
     seqnum: Option<u32>,
 }
 impl EosBuilder {
-    pub fn new() -> Self {
+    fn new() -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1139,7 +1185,8 @@ pub struct ErrorBuilder<'a> {
     details: Option<Structure>,
 }
 impl<'a> ErrorBuilder<'a> {
-    pub fn new(error: &'a glib::Error) -> Self {
+    fn new(error: &'a glib::Error) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1199,7 +1246,8 @@ pub struct WarningBuilder<'a> {
     details: Option<Structure>,
 }
 impl<'a> WarningBuilder<'a> {
-    pub fn new(error: &'a glib::Error) -> Self {
+    fn new(error: &'a glib::Error) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1259,7 +1307,8 @@ pub struct InfoBuilder<'a> {
     details: Option<Structure>,
 }
 impl<'a> InfoBuilder<'a> {
-    pub fn new(error: &'a glib::Error) -> Self {
+    fn new(error: &'a glib::Error) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1316,7 +1365,8 @@ pub struct TagBuilder<'a> {
     tags: &'a TagList,
 }
 impl<'a> TagBuilder<'a> {
-    pub fn new(tags: &'a TagList) -> Self {
+    fn new(tags: &'a TagList) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1336,7 +1386,8 @@ pub struct BufferingBuilder {
     stats: Option<(::BufferingMode, i32, i32, i64)>,
 }
 impl BufferingBuilder {
-    pub fn new(percent: i32) -> Self {
+    fn new(percent: i32) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1352,6 +1403,7 @@ impl BufferingBuilder {
         avg_out: i32,
         buffering_left: i64,
     ) -> Self {
+        skip_assert_initialized!();
         Self {
             stats: Some((mode, avg_in, avg_out, buffering_left)),
             ..self
@@ -1383,7 +1435,8 @@ pub struct StateChangedBuilder {
     pending: ::State,
 }
 impl StateChangedBuilder {
-    pub fn new(old: ::State, new: ::State, pending: ::State) -> Self {
+    fn new(old: ::State, new: ::State, pending: ::State) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1408,7 +1461,8 @@ pub struct StateDirtyBuilder {
     seqnum: Option<u32>,
 }
 impl StateDirtyBuilder {
-    pub fn new() -> Self {
+    fn new() -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1430,7 +1484,7 @@ pub struct StepDoneBuilder {
     eos: bool,
 }
 impl StepDoneBuilder {
-    pub fn new(
+    fn new(
         format: ::Format,
         amount: u64,
         rate: f64,
@@ -1439,6 +1493,7 @@ impl StepDoneBuilder {
         duration: u64,
         eos: bool,
     ) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1473,7 +1528,8 @@ pub struct ClockProvideBuilder<'a> {
     ready: bool,
 }
 impl<'a> ClockProvideBuilder<'a> {
-    pub fn new(clock: &'a ::Clock, ready: bool) -> Self {
+    fn new(clock: &'a ::Clock, ready: bool) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1493,7 +1549,8 @@ pub struct ClockLostBuilder<'a> {
     clock: &'a ::Clock,
 }
 impl<'a> ClockLostBuilder<'a> {
-    pub fn new(clock: &'a ::Clock) -> Self {
+    fn new(clock: &'a ::Clock) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1512,7 +1569,8 @@ pub struct NewClockBuilder<'a> {
     clock: &'a ::Clock,
 }
 impl<'a> NewClockBuilder<'a> {
-    pub fn new(clock: &'a ::Clock) -> Self {
+    fn new(clock: &'a ::Clock) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1533,7 +1591,8 @@ pub struct StructureChangeBuilder<'a> {
     busy: bool,
 }
 impl<'a> StructureChangeBuilder<'a> {
-    pub fn new(type_: ::StructureChangeType, owner: &'a ::Element, busy: bool) -> Self {
+    fn new(type_: ::StructureChangeType, owner: &'a ::Element, busy: bool) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1561,7 +1620,8 @@ pub struct StreamStatusBuilder<'a> {
     status_object: Option<&'a glib::Value>,
 }
 impl<'a> StreamStatusBuilder<'a> {
-    pub fn new(type_: ::StreamStatusType, owner: &'a ::Element) -> Self {
+    fn new(type_: ::StreamStatusType, owner: &'a ::Element) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1594,7 +1654,8 @@ pub struct ApplicationBuilder {
     structure: Option<::Structure>,
 }
 impl ApplicationBuilder {
-    pub fn new(structure: ::Structure) -> Self {
+    fn new(structure: ::Structure) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1613,7 +1674,8 @@ pub struct ElementBuilder {
     structure: Option<::Structure>,
 }
 impl ElementBuilder {
-    pub fn new(structure: ::Structure) -> Self {
+    fn new(structure: ::Structure) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1633,7 +1695,8 @@ pub struct SegmentStartBuilder {
     position: i64,
 }
 impl SegmentStartBuilder {
-    pub fn new(format: ::Format, position: i64) -> Self {
+    fn new(format: ::Format, position: i64) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1654,7 +1717,8 @@ pub struct SegmentDoneBuilder {
     position: i64,
 }
 impl SegmentDoneBuilder {
-    pub fn new(format: ::Format, position: i64) -> Self {
+    fn new(format: ::Format, position: i64) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1673,7 +1737,8 @@ pub struct DurationChangedBuilder {
     seqnum: Option<u32>,
 }
 impl DurationChangedBuilder {
-    pub fn new() -> Self {
+    fn new() -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1688,7 +1753,8 @@ pub struct LatencyBuilder {
     seqnum: Option<u32>,
 }
 impl LatencyBuilder {
-    pub fn new() -> Self {
+    fn new() -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1703,7 +1769,8 @@ pub struct AsyncStartBuilder {
     seqnum: Option<u32>,
 }
 impl AsyncStartBuilder {
-    pub fn new() -> Self {
+    fn new() -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1719,7 +1786,8 @@ pub struct AsyncDoneBuilder {
     running_time: u64,
 }
 impl AsyncDoneBuilder {
-    pub fn new(running_time: u64) -> Self {
+    fn new(running_time: u64) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1738,7 +1806,8 @@ pub struct RequestStateBuilder {
     state: ::State,
 }
 impl RequestStateBuilder {
-    pub fn new(state: ::State) -> Self {
+    fn new(state: ::State) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1762,7 +1831,7 @@ pub struct StepStartBuilder {
     intermediate: bool,
 }
 impl StepStartBuilder {
-    pub fn new(
+    fn new(
         active: bool,
         format: ::Format,
         amount: u64,
@@ -1770,6 +1839,7 @@ impl StepStartBuilder {
         flush: bool,
         intermediate: bool,
     ) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1807,13 +1877,14 @@ pub struct QosBuilder {
     stats: Option<(::Format, u64, u64)>,
 }
 impl QosBuilder {
-    pub fn new(
+    fn new(
         live: bool,
         running_time: u64,
         stream_time: u64,
         timestamp: u64,
         duration: u64,
     ) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1868,7 +1939,8 @@ pub struct ProgressBuilder<'a> {
     text: Option<&'a str>,
 }
 impl<'a> ProgressBuilder<'a> {
-    pub fn new(type_: ::ProgressType) -> Self {
+    fn new(type_: ::ProgressType) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1909,7 +1981,8 @@ pub struct TocBuilder<'a> {
     updated: bool,
 }
 impl<'a> TocBuilder<'a> {
-    pub fn new(toc: &'a ::Toc, updated: bool) -> Self {
+    fn new(toc: &'a ::Toc, updated: bool) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1929,7 +2002,8 @@ pub struct ResetTimeBuilder {
     running_time: u64,
 }
 impl ResetTimeBuilder {
-    pub fn new(running_time: u64) -> Self {
+    fn new(running_time: u64) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1948,7 +2022,8 @@ pub struct StreamStartBuilder {
     group_id: Option<u32>,
 }
 impl StreamStartBuilder {
-    pub fn new() -> Self {
+    fn new() -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1978,7 +2053,8 @@ pub struct NeedContextBuilder<'a> {
     context_type: &'a str,
 }
 impl<'a> NeedContextBuilder<'a> {
-    pub fn new(context_type: &'a str) -> Self {
+    fn new(context_type: &'a str) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -1997,7 +2073,8 @@ pub struct HaveContextBuilder {
     context: Option<::Context>,
 }
 impl HaveContextBuilder {
-    pub fn new(context: ::Context) -> Self {
+    fn new(context: ::Context) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -2017,7 +2094,8 @@ pub struct DeviceAddedBuilder<'a> {
     device: &'a ::Device,
 }
 impl<'a> DeviceAddedBuilder<'a> {
-    pub fn new(device: &'a ::Device) -> Self {
+    fn new(device: &'a ::Device) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -2036,7 +2114,8 @@ pub struct DeviceRemovedBuilder<'a> {
     device: &'a ::Device,
 }
 impl<'a> DeviceRemovedBuilder<'a> {
-    pub fn new(device: &'a ::Device) -> Self {
+    fn new(device: &'a ::Device) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -2058,7 +2137,8 @@ pub struct PropertyNotifyBuilder<'a> {
 }
 #[cfg(feature = "v1_10")]
 impl<'a> PropertyNotifyBuilder<'a> {
-    pub fn new(property_name: &'a str, value: &'a glib::Value) -> Self {
+    fn new(property_name: &'a str, value: &'a glib::Value) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -2084,7 +2164,8 @@ pub struct StreamCollectionBuilder<'a> {
 }
 #[cfg(feature = "v1_10")]
 impl<'a> StreamCollectionBuilder<'a> {
-    pub fn new(collection: &'a ::StreamCollection) -> Self {
+    fn new(collection: &'a ::StreamCollection) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -2108,7 +2189,8 @@ pub struct StreamsSelectedBuilder<'a> {
 }
 #[cfg(feature = "v1_10")]
 impl<'a> StreamsSelectedBuilder<'a> {
-    pub fn new(collection: &'a ::StreamCollection) -> Self {
+    fn new(collection: &'a ::StreamCollection) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -2146,11 +2228,12 @@ pub struct RedirectBuilder<'a> {
 }
 #[cfg(feature = "v1_10")]
 impl<'a> RedirectBuilder<'a> {
-    pub fn new(
+    fn new(
         location: &'a str,
         tag_list: Option<&'a TagList>,
         entry_struct: Option<Structure>,
     ) -> Self {
+        skip_assert_initialized!();
         Self {
             src: None,
             seqnum: None,
@@ -2165,6 +2248,7 @@ impl<'a> RedirectBuilder<'a> {
         self,
         entries: &'a [(&'a str, Option<&'a TagList>, Option<&'a Structure>)],
     ) -> Self {
+        skip_assert_initialized!();
         Self {
             entries: Some(entries),
             ..self
diff --git a/gstreamer/src/miniobject.rs b/gstreamer/src/miniobject.rs
index cb9b94f9c..4f9be07f1 100644
--- a/gstreamer/src/miniobject.rs
+++ b/gstreamer/src/miniobject.rs
@@ -244,6 +244,7 @@ impl<'a, T: MiniObject + 'static> ToGlibContainerFromSlice<'a, *mut *mut T::GstT
     type Storage = (Vec<Stash<'a, *mut T::GstType, GstRc<T>>>, Option<Vec<*mut T::GstType>>);
 
     fn to_glib_none_from_slice(t: &'a [GstRc<T>]) -> (*mut *mut T::GstType, Self::Storage) {
+        skip_assert_initialized!();
         let v: Vec<_> = t.iter().map(|s| s.to_glib_none()).collect();
         let mut v_ptr: Vec<_> = v.iter().map(|s| s.0).collect();
         v_ptr.push(ptr::null_mut() as *mut T::GstType);
@@ -252,6 +253,7 @@ impl<'a, T: MiniObject + 'static> ToGlibContainerFromSlice<'a, *mut *mut T::GstT
     }
 
     fn to_glib_container_from_slice(t: &'a [GstRc<T>]) -> (*mut *mut T::GstType, Self::Storage) {
+        skip_assert_initialized!();
         let v: Vec<_> = t.iter().map(|s| s.to_glib_none()).collect();
 
         let v_ptr = unsafe {
@@ -268,6 +270,7 @@ impl<'a, T: MiniObject + 'static> ToGlibContainerFromSlice<'a, *mut *mut T::GstT
     }
 
     fn to_glib_full_from_slice(t: &[GstRc<T>]) -> *mut *mut T::GstType {
+        skip_assert_initialized!();
         unsafe {
             let v_ptr = glib_ffi::g_malloc0(mem::size_of::<*mut T::GstType>() * t.len() + 1) as *mut *mut T::GstType;
 
@@ -284,16 +287,19 @@ impl<'a, T: MiniObject + 'static> ToGlibContainerFromSlice<'a, *const *mut T::Gs
     type Storage = (Vec<Stash<'a, *mut T::GstType, GstRc<T>>>, Option<Vec<*mut T::GstType>>);
 
     fn to_glib_none_from_slice(t: &'a [GstRc<T>]) -> (*const *mut T::GstType, Self::Storage) {
+        skip_assert_initialized!();
         let (ptr, stash) = ToGlibContainerFromSlice::<'a, *mut *mut T::GstType>::to_glib_none_from_slice(t);
         (ptr as *const *mut T::GstType, stash)
     }
 
     fn to_glib_container_from_slice(_: &'a [GstRc<T>]) -> (*const *mut T::GstType, Self::Storage) {
+        skip_assert_initialized!();
         // Can't have consumer free a *const pointer
         unimplemented!()
     }
 
     fn to_glib_full_from_slice(_: &[GstRc<T>]) -> *const *mut T::GstType {
+        skip_assert_initialized!();
         // Can't have consumer free a *const pointer
         unimplemented!()
     }
diff --git a/gstreamer/src/pad.rs b/gstreamer/src/pad.rs
index 85c952ed8..0f333780f 100644
--- a/gstreamer/src/pad.rs
+++ b/gstreamer/src/pad.rs
@@ -45,6 +45,7 @@ impl ToGlib for PadProbeId {
 
 impl FromGlib<libc::c_ulong> for PadProbeId {
     fn from_glib(val: libc::c_ulong) -> PadProbeId {
+        skip_assert_initialized!();
         PadProbeId(val)
     }
 }
@@ -208,6 +209,7 @@ impl<O: IsA<Pad>> PadExtManual for O {
         parent: Q,
         query: &mut QueryRef,
     ) -> bool {
+        skip_assert_initialized!();
         let parent = parent.into();
         let parent = parent.to_glib_none();
         unsafe {
@@ -242,6 +244,7 @@ impl<O: IsA<Pad>> PadExtManual for O {
         parent: Q,
         event: Event,
     ) -> bool {
+        skip_assert_initialized!();
         let parent = parent.into();
         let parent = parent.to_glib_none();
         unsafe {
diff --git a/gstreamer/src/query.rs b/gstreamer/src/query.rs
index 2212475a6..84ea5de13 100644
--- a/gstreamer/src/query.rs
+++ b/gstreamer/src/query.rs
@@ -29,26 +29,32 @@ unsafe impl MiniObject for QueryRef {
 
 impl Query {
     pub fn new_position(fmt: ::Format) -> Self {
+        assert_initialized_main_thread!();
         unsafe { from_glib_full(ffi::gst_query_new_position(fmt.to_glib())) }
     }
 
     pub fn new_duration(fmt: ::Format) -> Self {
+        assert_initialized_main_thread!();
         unsafe { from_glib_full(ffi::gst_query_new_duration(fmt.to_glib())) }
     }
 
     pub fn new_latency() -> Self {
+        assert_initialized_main_thread!();
         unsafe { from_glib_full(ffi::gst_query_new_latency()) }
     }
 
     pub fn new_seeking(fmt: ::Format) -> Self {
+        assert_initialized_main_thread!();
         unsafe { from_glib_full(ffi::gst_query_new_seeking(fmt.to_glib())) }
     }
 
     pub fn new_segment(fmt: ::Format) -> Self {
+        assert_initialized_main_thread!();
         unsafe { from_glib_full(ffi::gst_query_new_segment(fmt.to_glib())) }
     }
 
     pub fn new_convert(src_fmt: ::Format, value: i64, dest_fmt: ::Format) -> Self {
+        assert_initialized_main_thread!();
         unsafe {
             from_glib_full(ffi::gst_query_new_convert(
                 src_fmt.to_glib(),
@@ -59,14 +65,17 @@ impl Query {
     }
 
     pub fn new_formats() -> Self {
+        assert_initialized_main_thread!();
         unsafe { from_glib_full(ffi::gst_query_new_formats()) }
     }
 
     pub fn new_buffering(fmt: ::Format) -> Self {
+        assert_initialized_main_thread!();
         unsafe { from_glib_full(ffi::gst_query_new_buffering(fmt.to_glib())) }
     }
 
     pub fn new_custom(structure: ::Structure) -> Self {
+        assert_initialized_main_thread!();
         unsafe {
             from_glib_full(ffi::gst_query_new_custom(
                 ffi::GST_QUERY_CUSTOM,
@@ -76,26 +85,32 @@ impl Query {
     }
 
     pub fn new_uri() -> Self {
+        assert_initialized_main_thread!();
         unsafe { from_glib_full(ffi::gst_query_new_uri()) }
     }
 
     pub fn new_scheduling() -> Self {
+        assert_initialized_main_thread!();
         unsafe { from_glib_full(ffi::gst_query_new_scheduling()) }
     }
 
     pub fn new_accept_caps(caps: &::Caps) -> Self {
+        assert_initialized_main_thread!();
         unsafe { from_glib_full(ffi::gst_query_new_accept_caps(caps.as_mut_ptr())) }
     }
 
     pub fn new_caps(filter: &::Caps) -> Self {
+        assert_initialized_main_thread!();
         unsafe { from_glib_full(ffi::gst_query_new_caps(filter.as_mut_ptr())) }
     }
 
     pub fn new_drain() -> Self {
+        assert_initialized_main_thread!();
         unsafe { from_glib_full(ffi::gst_query_new_drain()) }
     }
 
     pub fn new_context(context_type: &str) -> Self {
+        assert_initialized_main_thread!();
         unsafe { from_glib_full(ffi::gst_query_new_context(context_type.to_glib_none().0)) }
     }
 }
@@ -584,6 +599,7 @@ impl<'a> Buffering<&'a mut QueryRef> {
         avg_out: i32,
         buffering_left: i64,
     ) {
+        skip_assert_initialized!();
         unsafe {
             ffi::gst_query_set_buffering_stats(
                 self.0.as_mut_ptr(),
@@ -698,6 +714,7 @@ impl<'a> Scheduling<&'a QueryRef> {
         mode: ::PadMode,
         flags: ::SchedulingFlags,
     ) -> bool {
+        skip_assert_initialized!();
         unsafe {
             from_glib(ffi::gst_query_has_scheduling_mode_with_flags(
                 self.0.as_mut_ptr(),
diff --git a/gstreamer/src/segment.rs b/gstreamer/src/segment.rs
index 6fc6bece2..963525988 100644
--- a/gstreamer/src/segment.rs
+++ b/gstreamer/src/segment.rs
@@ -61,6 +61,7 @@ impl Segment {
         stop_type: SeekType,
         stop: u64,
     ) -> Option<bool> {
+        skip_assert_initialized!();
         unsafe {
             let mut update = mem::uninitialized();
             let ret = from_glib(ffi::gst_segment_do_seek(
diff --git a/gstreamer/src/structure.rs b/gstreamer/src/structure.rs
index 8a545f3d1..7e4eb14b3 100644
--- a/gstreamer/src/structure.rs
+++ b/gstreamer/src/structure.rs
@@ -132,6 +132,7 @@ impl str::FromStr for Structure {
     type Err = ();
 
     fn from_str(s: &str) -> Result<Self, ()> {
+        skip_assert_initialized!();
         Structure::from_string(s).ok_or(())
     }
 }
@@ -446,6 +447,8 @@ impl StructureRef {
         name: &str,
         target: T,
     ) -> bool {
+        skip_assert_initialized!();
+
         let target = target.into();
         unsafe {
             from_glib(ffi::gst_structure_fixate_field_nearest_fraction(
@@ -489,7 +492,8 @@ pub struct FieldIterator<'a> {
 }
 
 impl<'a> FieldIterator<'a> {
-    pub fn new(structure: &'a StructureRef) -> FieldIterator<'a> {
+    fn new(structure: &'a StructureRef) -> FieldIterator<'a> {
+        skip_assert_initialized!();
         let n_fields = structure.n_fields();
 
         FieldIterator {
@@ -549,7 +553,8 @@ pub struct Iter<'a> {
 }
 
 impl<'a> Iter<'a> {
-    pub fn new(structure: &'a StructureRef) -> Iter<'a> {
+    fn new(structure: &'a StructureRef) -> Iter<'a> {
+        skip_assert_initialized!();
         Iter {
             iter: FieldIterator::new(structure),
         }
diff --git a/gstreamer/src/tags.rs b/gstreamer/src/tags.rs
index 636871cd5..10ac8d5d7 100644
--- a/gstreamer/src/tags.rs
+++ b/gstreamer/src/tags.rs
@@ -351,6 +351,7 @@ pub struct TagIterator<'a, T: Tag<'a>> {
 
 impl<'a, T: Tag<'a>> TagIterator<'a, T> {
     fn new(taglist: &'a TagListRef) -> TagIterator<'a, T> {
+        skip_assert_initialized!();
         TagIterator {
             taglist: taglist,
             idx: 0,
diff --git a/gstreamer/src/value.rs b/gstreamer/src/value.rs
index 803ebe3db..d371d0b79 100644
--- a/gstreamer/src/value.rs
+++ b/gstreamer/src/value.rs
@@ -25,14 +25,17 @@ pub struct Fraction(pub Rational32);
 
 impl Fraction {
     pub fn new(num: i32, den: i32) -> Fraction {
+        assert_initialized_main_thread!();
         (num, den).into()
     }
 
     pub fn approximate_f32(x: f32) -> Option<Fraction> {
+        assert_initialized_main_thread!();
         Rational32::approximate_float(x).map(|r| r.into())
     }
 
     pub fn approximate_f64(x: f64) -> Option<Fraction> {
+        assert_initialized_main_thread!();
         Rational32::approximate_float(x).map(|r| r.into())
     }
 }
@@ -153,12 +156,14 @@ impl ops::Neg for Fraction {
 
 impl From<i32> for Fraction {
     fn from(x: i32) -> Fraction {
+        assert_initialized_main_thread!();
         Fraction(x.into())
     }
 }
 
 impl From<(i32, i32)> for Fraction {
     fn from(x: (i32, i32)) -> Fraction {
+        assert_initialized_main_thread!();
         Fraction(x.into())
     }
 }
@@ -171,12 +176,14 @@ impl Into<(i32, i32)> for Fraction {
 
 impl From<Rational32> for Fraction {
     fn from(x: Rational32) -> Fraction {
+        assert_initialized_main_thread!();
         Fraction(x)
     }
 }
 
 impl From<Fraction> for Rational32 {
     fn from(x: Fraction) -> Rational32 {
+        skip_assert_initialized!();
         x.0
     }
 }
@@ -231,10 +238,13 @@ impl<T: Copy> IntRange<T> {
 
 impl IntRange<i32> {
     pub fn new(min: i32, max: i32) -> Self {
+        skip_assert_initialized!();
         Self::new_with_step(min, max, 1)
     }
 
     pub fn new_with_step(min: i32, max: i32, step: i32) -> Self {
+        assert_initialized_main_thread!();
+
         assert!(min <= max);
         assert!(step > 0);
 
@@ -248,10 +258,13 @@ impl IntRange<i32> {
 
 impl IntRange<i64> {
     pub fn new(min: i64, max: i64) -> Self {
+        skip_assert_initialized!();
         Self::new_with_step(min, max, 1)
     }
 
     pub fn new_with_step(min: i64, max: i64, step: i64) -> Self {
+        assert_initialized_main_thread!();
+
         assert!(min <= max);
         assert!(step > 0);
 
@@ -265,24 +278,28 @@ impl IntRange<i64> {
 
 impl From<(i32, i32)> for IntRange<i32> {
     fn from((min, max): (i32, i32)) -> Self {
+        skip_assert_initialized!();
         Self::new(min, max)
     }
 }
 
 impl From<(i32, i32, i32)> for IntRange<i32> {
     fn from((min, max, step): (i32, i32, i32)) -> Self {
+        skip_assert_initialized!();
         Self::new_with_step(min, max, step)
     }
 }
 
 impl From<(i64, i64)> for IntRange<i64> {
     fn from((min, max): (i64, i64)) -> Self {
+        skip_assert_initialized!();
         Self::new(min, max)
     }
 }
 
 impl From<(i64, i64, i64)> for IntRange<i64> {
     fn from((min, max, step): (i64, i64, i64)) -> Self {
+        skip_assert_initialized!();
         Self::new_with_step(min, max, step)
     }
 }
@@ -351,6 +368,8 @@ pub struct FractionRange {
 
 impl FractionRange {
     pub fn new<T: Into<Fraction>, U: Into<Fraction>>(min: T, max: U) -> Self {
+        assert_initialized_main_thread!();
+
         let min = min.into();
         let max = max.into();
 
@@ -370,6 +389,8 @@ impl FractionRange {
 
 impl From<(Fraction, Fraction)> for FractionRange {
     fn from((min, max): (Fraction, Fraction)) -> Self {
+        skip_assert_initialized!();
+
         Self::new(min, max)
     }
 }
@@ -417,6 +438,7 @@ pub struct Bitmask(u64);
 
 impl Bitmask {
     pub fn new(v: u64) -> Self {
+        assert_initialized_main_thread!();
         Bitmask(v)
     }
 }
@@ -469,6 +491,7 @@ impl ops::Not for Bitmask {
 
 impl From<u64> for Bitmask {
     fn from(v: u64) -> Self {
+        skip_assert_initialized!();
         Self::new(v)
     }
 }
@@ -503,6 +526,8 @@ pub struct Array<'a>(Cow<'a, [glib::Value]>);
 
 impl<'a> Array<'a> {
     pub fn new(values: &[&ToValue]) -> Self {
+        assert_initialized_main_thread!();
+
         Array(values.iter().map(|v| v.to_value()).collect())
     }
 
@@ -517,12 +542,16 @@ impl<'a> Array<'a> {
 
 impl<'a> From<&'a [&'a ToValue]> for Array<'a> {
     fn from(values: &'a [&'a ToValue]) -> Self {
+        skip_assert_initialized!();
+
         Self::new(values)
     }
 }
 
 impl<'a> From<&'a [glib::Value]> for Array<'a> {
     fn from(values: &'a [glib::Value]) -> Self {
+        assert_initialized_main_thread!();
+
         Array(Cow::Borrowed(values))
     }
 }
@@ -566,6 +595,8 @@ pub struct List<'a>(Cow<'a, [glib::Value]>);
 
 impl<'a> List<'a> {
     pub fn new(values: &[&ToValue]) -> Self {
+        assert_initialized_main_thread!();
+
         List(values.iter().map(|v| v.to_value()).collect())
     }
 
@@ -580,12 +611,16 @@ impl<'a> List<'a> {
 
 impl<'a> From<&'a [&'a ToValue]> for List<'a> {
     fn from(values: &'a [&'a ToValue]) -> Self {
+        skip_assert_initialized!();
+
         Self::new(values)
     }
 }
 
 impl<'a> From<&'a [glib::Value]> for List<'a> {
     fn from(values: &'a [glib::Value]) -> Self {
+        assert_initialized_main_thread!();
+
         List(Cow::Borrowed(values))
     }
 }
@@ -646,6 +681,8 @@ impl ToGlib for ValueOrder {
 
 impl FromGlib<i32> for ValueOrder {
     fn from_glib(v: i32) -> Self {
+        skip_assert_initialized!();
+
         match v {
             ffi::GST_VALUE_LESS_THAN => ValueOrder::LessThan,
             ffi::GST_VALUE_EQUAL => ValueOrder::Equal,
@@ -799,6 +836,8 @@ impl GstValueExt for glib::Value {
     }
 
     fn deserialize<'a, T: Into<&'a str>>(s: T) -> Option<glib::Value> {
+        assert_initialized_main_thread!();
+
         let s = s.into();
 
         unsafe {