diff --git a/CHANGES.md b/CHANGES.md
index 0cb5ccb23..784500d9e 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,6 +1,16 @@
 # Changes
 
 ## Unreleased - 2021-xx-xx
+### Changed
+* Compress middleware's response type is now `AnyBody<Encoder<B>>`. [#2448]
+
+### Fixed
+* Relax `Unpin` bound on `S` (stream) parameter of `HttpResponseBuilder::streaming`. [#2448]
+
+### Removed
+* `dev::ResponseBody` re-export; is function is replaced by the new `dev::AnyBody` enum. [#2446]
+
+[#2423]: https://github.com/actix/actix-web/pull/2423
 
 
 ## 4.0.0-beta.11 - 2021-11-15
diff --git a/actix-http/CHANGES.md b/actix-http/CHANGES.md
index 2beda3dcc..71cdd6d4c 100644
--- a/actix-http/CHANGES.md
+++ b/actix-http/CHANGES.md
@@ -2,14 +2,23 @@
 
 ## Unreleased - 2021-xx-xx
 ### Added
-* `AnyBody::empty` for quickly creating an empty body. [#2446]
+* `body::AnyBody::empty` for quickly creating an empty body. [#2446]
+* `impl Clone` for `body::AnyBody<S> where S: Clone`. [#2448]
+* `body::AnyBody::into_boxed` for quickly converting to a type-erased, boxed body type. [#2448]
 
 ### Changed
-* Rename `AnyBody::{Message => Stream}`. [#2446]
+* Rename `body::AnyBody::{Message => Body}`. [#2446]
+* Rename `body::AnyBody::{from_message => new_boxed}`. [#2448]
+* Rename `body::AnyBody::{from_slice => copy_from_slice}`. [#2448]
+* Rename `body::{BoxAnyBody => BoxBody}`. [#2448]
+* Change representation of `AnyBody` to include a type parameter in `Body` variant. Defaults to `BoxBody`. [#2448]
+* `Encoder::response` now returns `AnyBody<Encoder<B>>`. [#2448]
 
 ### Removed
-* `AnyBody::Empty`; an empty body can now only be represented as a zero-length `Bytes` variant. [#2446]
-* `BodySize::Empty`; an empty body can now only be represented as a `Sized(0)` variant. [#2446]
+* `body::AnyBody::Empty`; an empty body can now only be represented as a zero-length `Bytes` variant. [#2446]
+* `body::BodySize::Empty`; an empty body can now only be represented as a `Sized(0)` variant. [#2446]
+* `EncoderError::Boxed`; it is no longer required. [#2446]
+* `body::ResponseBody`; is function is replaced by the new `body::AnyBody` enum. [#2446]
 
 [#2446]: https://github.com/actix/actix-web/pull/2446
 
diff --git a/actix-http/Cargo.toml b/actix-http/Cargo.toml
index 784312445..27a147379 100644
--- a/actix-http/Cargo.toml
+++ b/actix-http/Cargo.toml
@@ -92,6 +92,7 @@ regex = "1.3"
 rustls-pemfile = "0.2"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
+static_assertions = "1"
 tls-openssl = { package = "openssl", version = "0.10.9" }
 tls-rustls = { package = "rustls", version = "0.20.0" }
 tokio = { version = "1.2", features = ["net", "rt"] }
diff --git a/actix-http/src/body/body.rs b/actix-http/src/body/body.rs
index 32b464486..d51173a57 100644
--- a/actix-http/src/body/body.rs
+++ b/actix-http/src/body/body.rs
@@ -8,6 +8,7 @@ use std::{
 
 use bytes::{Bytes, BytesMut};
 use futures_core::Stream;
+use pin_project::pin_project;
 
 use crate::error::Error;
 
@@ -16,15 +17,17 @@ use super::{BodySize, BodyStream, MessageBody, MessageBodyMapErr, SizedStream};
 pub type Body = AnyBody;
 
 /// Represents various types of HTTP message body.
-pub enum AnyBody {
+#[pin_project(project = AnyBodyProj)]
+#[derive(Clone)]
+pub enum AnyBody<B = BoxBody> {
     /// Empty response. `Content-Length` header is not set.
     None,
 
-    /// Specific response body.
+    /// Complete, in-memory response body.
     Bytes(Bytes),
 
-    /// Generic message body.
-    Stream(BoxAnyBody),
+    /// Generic / Other message body.
+    Body(#[pin] B),
 }
 
 impl AnyBody {
@@ -33,29 +36,60 @@ impl AnyBody {
         Self::Bytes(Bytes::new())
     }
 
-    /// Create body from slice (copy)
-    pub fn from_slice(s: &[u8]) -> Self {
-        Self::Bytes(Bytes::copy_from_slice(s))
-    }
-
-    /// Create body from generic message body.
-    pub fn from_message<B>(body: B) -> Self
+    /// Create boxed body from generic message body.
+    pub fn new_boxed<B>(body: B) -> Self
     where
         B: MessageBody + 'static,
         B::Error: Into<Box<dyn StdError + 'static>>,
     {
-        Self::Stream(BoxAnyBody::from_body(body))
+        Self::Body(BoxBody::from_body(body))
+    }
+
+    /// Constructs new `AnyBody` instance from a slice of bytes by copying it.
+    ///
+    /// If your bytes container is owned, it may be cheaper to use a `From` impl.
+    pub fn copy_from_slice(s: &[u8]) -> Self {
+        Self::Bytes(Bytes::copy_from_slice(s))
+    }
+
+    #[doc(hidden)]
+    #[deprecated(since = "4.0.0", note = "Renamed to `copy_from_slice`.")]
+    pub fn from_slice(s: &[u8]) -> Self {
+        Self::Bytes(Bytes::copy_from_slice(s))
     }
 }
 
-impl MessageBody for AnyBody {
+impl<B> AnyBody<B>
+where
+    B: MessageBody + 'static,
+    B::Error: Into<Box<dyn StdError + 'static>>,
+{
+    /// Create body from generic message body.
+    pub fn new(body: B) -> Self {
+        Self::Body(body)
+    }
+
+    pub fn into_boxed(self) -> AnyBody {
+        match self {
+            Self::None => AnyBody::None,
+            Self::Bytes(bytes) => AnyBody::Bytes(bytes),
+            Self::Body(body) => AnyBody::new_boxed(body),
+        }
+    }
+}
+
+impl<B> MessageBody for AnyBody<B>
+where
+    B: MessageBody,
+    B::Error: Into<Box<dyn StdError>> + 'static,
+{
     type Error = Error;
 
     fn size(&self) -> BodySize {
         match self {
             AnyBody::None => BodySize::None,
             AnyBody::Bytes(ref bin) => BodySize::Sized(bin.len() as u64),
-            AnyBody::Stream(ref body) => body.size(),
+            AnyBody::Body(ref body) => body.size(),
         }
     }
 
@@ -63,9 +97,9 @@ impl MessageBody for AnyBody {
         self: Pin<&mut Self>,
         cx: &mut Context<'_>,
     ) -> Poll<Option<Result<Bytes, Self::Error>>> {
-        match self.get_mut() {
-            AnyBody::None => Poll::Ready(None),
-            AnyBody::Bytes(ref mut bin) => {
+        match self.project() {
+            AnyBodyProj::None => Poll::Ready(None),
+            AnyBodyProj::Bytes(bin) => {
                 let len = bin.len();
                 if len == 0 {
                     Poll::Ready(None)
@@ -74,8 +108,7 @@ impl MessageBody for AnyBody {
                 }
             }
 
-            AnyBody::Stream(body) => body
-                .as_pin_mut()
+            AnyBodyProj::Body(body) => body
                 .poll_next(cx)
                 .map_err(|err| Error::new_body().with_cause(err)),
         }
@@ -90,30 +123,30 @@ impl PartialEq for AnyBody {
                 AnyBody::Bytes(ref b2) => b == b2,
                 _ => false,
             },
-            AnyBody::Stream(_) => false,
+            AnyBody::Body(_) => false,
         }
     }
 }
 
-impl fmt::Debug for AnyBody {
+impl<S: fmt::Debug> fmt::Debug for AnyBody<S> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
             AnyBody::None => write!(f, "AnyBody::None"),
-            AnyBody::Bytes(ref b) => write!(f, "AnyBody::Bytes({:?})", b),
-            AnyBody::Stream(_) => write!(f, "AnyBody::Message(_)"),
+            AnyBody::Bytes(ref bytes) => write!(f, "AnyBody::Bytes({:?})", bytes),
+            AnyBody::Body(ref stream) => write!(f, "AnyBody::Message({:?})", stream),
         }
     }
 }
 
 impl From<&'static str> for AnyBody {
-    fn from(s: &'static str) -> Body {
-        AnyBody::Bytes(Bytes::from_static(s.as_ref()))
+    fn from(string: &'static str) -> Body {
+        AnyBody::Bytes(Bytes::from_static(string.as_ref()))
     }
 }
 
 impl From<&'static [u8]> for AnyBody {
-    fn from(s: &'static [u8]) -> Body {
-        AnyBody::Bytes(Bytes::from_static(s))
+    fn from(bytes: &'static [u8]) -> Body {
+        AnyBody::Bytes(Bytes::from_static(bytes))
     }
 }
 
@@ -124,20 +157,20 @@ impl From<Vec<u8>> for AnyBody {
 }
 
 impl From<String> for AnyBody {
-    fn from(s: String) -> Body {
-        s.into_bytes().into()
+    fn from(string: String) -> Body {
+        string.into_bytes().into()
     }
 }
 
 impl From<&'_ String> for AnyBody {
-    fn from(s: &String) -> Body {
-        AnyBody::Bytes(Bytes::copy_from_slice(AsRef::<[u8]>::as_ref(&s)))
+    fn from(string: &String) -> Body {
+        AnyBody::Bytes(Bytes::copy_from_slice(AsRef::<[u8]>::as_ref(&string)))
     }
 }
 
 impl From<Cow<'_, str>> for AnyBody {
-    fn from(s: Cow<'_, str>) -> Body {
-        match s {
+    fn from(string: Cow<'_, str>) -> Body {
+        match string {
             Cow::Owned(s) => AnyBody::from(s),
             Cow::Borrowed(s) => {
                 AnyBody::Bytes(Bytes::copy_from_slice(AsRef::<[u8]>::as_ref(s)))
@@ -147,14 +180,14 @@ impl From<Cow<'_, str>> for AnyBody {
 }
 
 impl From<Bytes> for AnyBody {
-    fn from(s: Bytes) -> Body {
-        AnyBody::Bytes(s)
+    fn from(bytes: Bytes) -> Body {
+        AnyBody::Bytes(bytes)
     }
 }
 
 impl From<BytesMut> for AnyBody {
-    fn from(s: BytesMut) -> Body {
-        AnyBody::Bytes(s.freeze())
+    fn from(bytes: BytesMut) -> Body {
+        AnyBody::Bytes(bytes.freeze())
     }
 }
 
@@ -163,8 +196,8 @@ where
     S: Stream<Item = Result<Bytes, E>> + 'static,
     E: Into<Box<dyn StdError>> + 'static,
 {
-    fn from(s: SizedStream<S>) -> Body {
-        AnyBody::from_message(s)
+    fn from(stream: SizedStream<S>) -> Body {
+        AnyBody::new_boxed(stream)
     }
 }
 
@@ -173,15 +206,15 @@ where
     S: Stream<Item = Result<Bytes, E>> + 'static,
     E: Into<Box<dyn StdError>> + 'static,
 {
-    fn from(s: BodyStream<S>) -> Body {
-        AnyBody::from_message(s)
+    fn from(stream: BodyStream<S>) -> Body {
+        AnyBody::new_boxed(stream)
     }
 }
 
 /// A boxed message body with boxed errors.
-pub struct BoxAnyBody(Pin<Box<dyn MessageBody<Error = Box<dyn StdError + 'static>>>>);
+pub struct BoxBody(Pin<Box<dyn MessageBody<Error = Box<dyn StdError>>>>);
 
-impl BoxAnyBody {
+impl BoxBody {
     /// Boxes a `MessageBody` and any errors it generates.
     pub fn from_body<B>(body: B) -> Self
     where
@@ -195,18 +228,18 @@ impl BoxAnyBody {
     /// Returns a mutable pinned reference to the inner message body type.
     pub fn as_pin_mut(
         &mut self,
-    ) -> Pin<&mut (dyn MessageBody<Error = Box<dyn StdError + 'static>>)> {
+    ) -> Pin<&mut (dyn MessageBody<Error = Box<dyn StdError>>)> {
         self.0.as_mut()
     }
 }
 
-impl fmt::Debug for BoxAnyBody {
+impl fmt::Debug for BoxBody {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str("BoxAnyBody(dyn MessageBody)")
     }
 }
 
-impl MessageBody for BoxAnyBody {
+impl MessageBody for BoxBody {
     type Error = Error;
 
     fn size(&self) -> BodySize {
@@ -223,3 +256,52 @@ impl MessageBody for BoxAnyBody {
             .map_err(|err| Error::new_body().with_cause(err))
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use std::marker::PhantomPinned;
+
+    use static_assertions::{assert_impl_all, assert_not_impl_all};
+
+    use super::*;
+    use crate::body::to_bytes;
+
+    struct PinType(PhantomPinned);
+
+    impl MessageBody for PinType {
+        type Error = crate::Error;
+
+        fn size(&self) -> BodySize {
+            unimplemented!()
+        }
+
+        fn poll_next(
+            self: Pin<&mut Self>,
+            _cx: &mut Context<'_>,
+        ) -> Poll<Option<Result<Bytes, Self::Error>>> {
+            unimplemented!()
+        }
+    }
+
+    assert_impl_all!(AnyBody<()>: MessageBody, fmt::Debug, Send, Sync, Unpin);
+    assert_impl_all!(AnyBody<AnyBody<()>>: MessageBody, fmt::Debug, Send, Sync, Unpin);
+    assert_impl_all!(AnyBody<Bytes>: MessageBody, fmt::Debug, Send, Sync, Unpin);
+    assert_impl_all!(AnyBody: MessageBody, fmt::Debug, Unpin);
+    assert_impl_all!(BoxBody: MessageBody, fmt::Debug, Unpin);
+    assert_impl_all!(AnyBody<PinType>: MessageBody);
+
+    assert_not_impl_all!(AnyBody: Send, Sync, Unpin);
+    assert_not_impl_all!(BoxBody: Send, Sync, Unpin);
+    assert_not_impl_all!(AnyBody<PinType>: Send, Sync, Unpin);
+
+    #[actix_rt::test]
+    async fn nested_boxed_body() {
+        let body = AnyBody::copy_from_slice(&[1, 2, 3]);
+        let boxed_body = BoxBody::from_body(BoxBody::from_body(body));
+
+        assert_eq!(
+            to_bytes(boxed_body).await.unwrap(),
+            Bytes::from(vec![1, 2, 3]),
+        );
+    }
+}
diff --git a/actix-http/src/body/body_stream.rs b/actix-http/src/body/body_stream.rs
index f726f4475..31de9b48f 100644
--- a/actix-http/src/body/body_stream.rs
+++ b/actix-http/src/body/body_stream.rs
@@ -75,10 +75,22 @@ mod tests {
     use derive_more::{Display, Error};
     use futures_core::ready;
     use futures_util::{stream, FutureExt as _};
+    use static_assertions::{assert_impl_all, assert_not_impl_all};
 
     use super::*;
     use crate::body::to_bytes;
 
+    assert_impl_all!(BodyStream<stream::Empty<Result<Bytes, crate::Error>>>: MessageBody);
+    assert_impl_all!(BodyStream<stream::Empty<Result<Bytes, &'static str>>>: MessageBody);
+    assert_impl_all!(BodyStream<stream::Repeat<Result<Bytes, &'static str>>>: MessageBody);
+    assert_impl_all!(BodyStream<stream::Empty<Result<Bytes, Infallible>>>: MessageBody);
+    assert_impl_all!(BodyStream<stream::Repeat<Result<Bytes, Infallible>>>: MessageBody);
+
+    assert_not_impl_all!(BodyStream<stream::Empty<Bytes>>: MessageBody);
+    assert_not_impl_all!(BodyStream<stream::Repeat<Bytes>>: MessageBody);
+    // crate::Error is not Clone
+    assert_not_impl_all!(BodyStream<stream::Repeat<Result<Bytes, crate::Error>>>: MessageBody);
+
     #[actix_rt::test]
     async fn skips_empty_chunks() {
         let body = BodyStream::new(stream::iter(
@@ -124,6 +136,30 @@ mod tests {
         assert!(matches!(to_bytes(body).await, Err(StreamErr)));
     }
 
+    #[actix_rt::test]
+    async fn stream_string_error() {
+        // `&'static str` does not impl `Error`
+        // but it does impl `Into<Box<dyn Error>>`
+
+        let body = BodyStream::new(stream::once(async { Err("stringy error") }));
+        assert!(matches!(to_bytes(body).await, Err("stringy error")));
+    }
+
+    #[actix_rt::test]
+    async fn stream_boxed_error() {
+        // `Box<dyn Error>` does not impl `Error`
+        // but it does impl `Into<Box<dyn Error>>`
+
+        let body = BodyStream::new(stream::once(async {
+            Err(Box::<dyn StdError>::from("stringy error"))
+        }));
+
+        assert_eq!(
+            to_bytes(body).await.unwrap_err().to_string(),
+            "stringy error"
+        );
+    }
+
     #[actix_rt::test]
     async fn stream_delayed_error() {
         let body =
diff --git a/actix-http/src/body/mod.rs b/actix-http/src/body/mod.rs
index 0d5b0f079..07e5e67ce 100644
--- a/actix-http/src/body/mod.rs
+++ b/actix-http/src/body/mod.rs
@@ -11,15 +11,13 @@ use futures_core::ready;
 mod body;
 mod body_stream;
 mod message_body;
-mod response_body;
 mod size;
 mod sized_stream;
 
-pub use self::body::{AnyBody, Body, BoxAnyBody};
+pub use self::body::{AnyBody, Body, BoxBody};
 pub use self::body_stream::BodyStream;
 pub use self::message_body::MessageBody;
 pub(crate) use self::message_body::MessageBodyMapErr;
-pub use self::response_body::ResponseBody;
 pub use self::size::BodySize;
 pub use self::sized_stream::SizedStream;
 
@@ -108,10 +106,10 @@ mod tests {
         assert_eq!(Body::from(b"test".as_ref()).size(), BodySize::Sized(4));
         assert_eq!(Body::from(b"test".as_ref()).get_ref(), b"test");
         assert_eq!(
-            Body::from_slice(b"test".as_ref()).size(),
+            Body::copy_from_slice(b"test".as_ref()).size(),
             BodySize::Sized(4)
         );
-        assert_eq!(Body::from_slice(b"test".as_ref()).get_ref(), b"test");
+        assert_eq!(Body::copy_from_slice(b"test".as_ref()).get_ref(), b"test");
         let sb = Bytes::from(&b"test"[..]);
         pin!(sb);
 
diff --git a/actix-http/src/body/response_body.rs b/actix-http/src/body/response_body.rs
deleted file mode 100644
index 699ea9384..000000000
--- a/actix-http/src/body/response_body.rs
+++ /dev/null
@@ -1,84 +0,0 @@
-use std::{
-    mem,
-    pin::Pin,
-    task::{Context, Poll},
-};
-
-use bytes::Bytes;
-use futures_core::Stream;
-use pin_project::pin_project;
-
-use crate::error::Error;
-
-use super::{Body, BodySize, MessageBody};
-
-#[pin_project(project = ResponseBodyProj)]
-pub enum ResponseBody<B> {
-    Body(#[pin] B),
-    Other(Body),
-}
-
-impl ResponseBody<Body> {
-    pub fn into_body<B>(self) -> ResponseBody<B> {
-        match self {
-            ResponseBody::Body(b) => ResponseBody::Other(b),
-            ResponseBody::Other(b) => ResponseBody::Other(b),
-        }
-    }
-}
-
-impl<B> ResponseBody<B> {
-    pub fn take_body(&mut self) -> ResponseBody<B> {
-        mem::replace(self, ResponseBody::Other(Body::None))
-    }
-}
-
-impl<B: MessageBody> ResponseBody<B> {
-    pub fn as_ref(&self) -> Option<&B> {
-        if let ResponseBody::Body(ref b) = self {
-            Some(b)
-        } else {
-            None
-        }
-    }
-}
-
-impl<B> MessageBody for ResponseBody<B>
-where
-    B: MessageBody,
-    B::Error: Into<Error>,
-{
-    type Error = Error;
-
-    fn size(&self) -> BodySize {
-        match self {
-            ResponseBody::Body(ref body) => body.size(),
-            ResponseBody::Other(ref body) => body.size(),
-        }
-    }
-
-    fn poll_next(
-        self: Pin<&mut Self>,
-        cx: &mut Context<'_>,
-    ) -> Poll<Option<Result<Bytes, Self::Error>>> {
-        Stream::poll_next(self, cx)
-    }
-}
-
-impl<B> Stream for ResponseBody<B>
-where
-    B: MessageBody,
-    B::Error: Into<Error>,
-{
-    type Item = Result<Bytes, Error>;
-
-    fn poll_next(
-        self: Pin<&mut Self>,
-        cx: &mut Context<'_>,
-    ) -> Poll<Option<Self::Item>> {
-        match self.project() {
-            ResponseBodyProj::Body(body) => body.poll_next(cx).map_err(Into::into),
-            ResponseBodyProj::Other(body) => Pin::new(body).poll_next(cx),
-        }
-    }
-}
diff --git a/actix-http/src/body/sized_stream.rs b/actix-http/src/body/sized_stream.rs
index b6ceb32fe..b92de44cc 100644
--- a/actix-http/src/body/sized_stream.rs
+++ b/actix-http/src/body/sized_stream.rs
@@ -72,10 +72,22 @@ mod tests {
     use actix_rt::pin;
     use actix_utils::future::poll_fn;
     use futures_util::stream;
+    use static_assertions::{assert_impl_all, assert_not_impl_all};
 
     use super::*;
     use crate::body::to_bytes;
 
+    assert_impl_all!(SizedStream<stream::Empty<Result<Bytes, crate::Error>>>: MessageBody);
+    assert_impl_all!(SizedStream<stream::Empty<Result<Bytes, &'static str>>>: MessageBody);
+    assert_impl_all!(SizedStream<stream::Repeat<Result<Bytes, &'static str>>>: MessageBody);
+    assert_impl_all!(SizedStream<stream::Empty<Result<Bytes, Infallible>>>: MessageBody);
+    assert_impl_all!(SizedStream<stream::Repeat<Result<Bytes, Infallible>>>: MessageBody);
+
+    assert_not_impl_all!(SizedStream<stream::Empty<Bytes>>: MessageBody);
+    assert_not_impl_all!(SizedStream<stream::Repeat<Bytes>>: MessageBody);
+    // crate::Error is not Clone
+    assert_not_impl_all!(SizedStream<stream::Repeat<Result<Bytes, crate::Error>>>: MessageBody);
+
     #[actix_rt::test]
     async fn skips_empty_chunks() {
         let body = SizedStream::new(
@@ -119,4 +131,37 @@ mod tests {
 
         assert_eq!(to_bytes(body).await.ok(), Some(Bytes::from("12")));
     }
+
+    #[actix_rt::test]
+    async fn stream_string_error() {
+        // `&'static str` does not impl `Error`
+        // but it does impl `Into<Box<dyn Error>>`
+
+        let body = SizedStream::new(0, stream::once(async { Err("stringy error") }));
+        assert_eq!(to_bytes(body).await, Ok(Bytes::new()));
+
+        let body = SizedStream::new(1, stream::once(async { Err("stringy error") }));
+        assert!(matches!(to_bytes(body).await, Err("stringy error")));
+    }
+
+    #[actix_rt::test]
+    async fn stream_boxed_error() {
+        // `Box<dyn Error>` does not impl `Error`
+        // but it does impl `Into<Box<dyn Error>>`
+
+        let body = SizedStream::new(
+            0,
+            stream::once(async { Err(Box::<dyn StdError>::from("stringy error")) }),
+        );
+        assert_eq!(to_bytes(body).await.unwrap(), Bytes::new());
+
+        let body = SizedStream::new(
+            1,
+            stream::once(async { Err(Box::<dyn StdError>::from("stringy error")) }),
+        );
+        assert_eq!(
+            to_bytes(body).await.unwrap_err().to_string(),
+            "stringy error"
+        );
+    }
 }
diff --git a/actix-http/src/encoding/encoder.rs b/actix-http/src/encoding/encoder.rs
index 6cb034b76..62100ff1d 100644
--- a/actix-http/src/encoding/encoder.rs
+++ b/actix-http/src/encoding/encoder.rs
@@ -24,7 +24,7 @@ use flate2::write::{GzEncoder, ZlibEncoder};
 use zstd::stream::write::Encoder as ZstdEncoder;
 
 use crate::{
-    body::{Body, BodySize, BoxAnyBody, MessageBody, ResponseBody},
+    body::{AnyBody, BodySize, MessageBody},
     http::{
         header::{ContentEncoding, CONTENT_ENCODING},
         HeaderValue, StatusCode,
@@ -50,8 +50,8 @@ impl<B: MessageBody> Encoder<B> {
     pub fn response(
         encoding: ContentEncoding,
         head: &mut ResponseHead,
-        body: ResponseBody<B>,
-    ) -> ResponseBody<Encoder<B>> {
+        body: AnyBody<B>,
+    ) -> AnyBody<Encoder<B>> {
         let can_encode = !(head.headers().contains_key(&CONTENT_ENCODING)
             || head.status == StatusCode::SWITCHING_PROTOCOLS
             || head.status == StatusCode::NO_CONTENT
@@ -59,18 +59,15 @@ impl<B: MessageBody> Encoder<B> {
             || encoding == ContentEncoding::Auto);
 
         let body = match body {
-            ResponseBody::Other(b) => match b {
-                Body::None => return ResponseBody::Other(Body::None),
-                Body::Bytes(buf) => {
-                    if can_encode {
-                        EncoderBody::Bytes(buf)
-                    } else {
-                        return ResponseBody::Other(Body::Bytes(buf));
-                    }
+            AnyBody::None => return AnyBody::None,
+            AnyBody::Bytes(buf) => {
+                if can_encode {
+                    EncoderBody::Bytes(buf)
+                } else {
+                    return AnyBody::Bytes(buf);
                 }
-                Body::Stream(stream) => EncoderBody::BoxedStream(stream),
-            },
-            ResponseBody::Body(stream) => EncoderBody::Stream(stream),
+            }
+            AnyBody::Body(body) => EncoderBody::Stream(body),
         };
 
         if can_encode {
@@ -78,7 +75,8 @@ impl<B: MessageBody> Encoder<B> {
             if let Some(enc) = ContentEncoder::encoder(encoding) {
                 update_head(encoding, head);
                 head.no_chunking(false);
-                return ResponseBody::Body(Encoder {
+
+                return AnyBody::Body(Encoder {
                     body,
                     eof: false,
                     fut: None,
@@ -87,7 +85,7 @@ impl<B: MessageBody> Encoder<B> {
             }
         }
 
-        ResponseBody::Body(Encoder {
+        AnyBody::Body(Encoder {
             body,
             eof: false,
             fut: None,
@@ -100,7 +98,6 @@ impl<B: MessageBody> Encoder<B> {
 enum EncoderBody<B> {
     Bytes(Bytes),
     Stream(#[pin] B),
-    BoxedStream(BoxAnyBody),
 }
 
 impl<B> MessageBody for EncoderBody<B>
@@ -113,7 +110,6 @@ where
         match self {
             EncoderBody::Bytes(ref b) => b.size(),
             EncoderBody::Stream(ref b) => b.size(),
-            EncoderBody::BoxedStream(ref b) => b.size(),
         }
     }
 
@@ -130,9 +126,6 @@ where
                 }
             }
             EncoderBodyProj::Stream(b) => b.poll_next(cx).map_err(EncoderError::Body),
-            EncoderBodyProj::BoxedStream(ref mut b) => {
-                b.as_pin_mut().poll_next(cx).map_err(EncoderError::Boxed)
-            }
         }
     }
 }
@@ -348,9 +341,6 @@ pub enum EncoderError<E> {
     #[display(fmt = "body")]
     Body(E),
 
-    #[display(fmt = "boxed")]
-    Boxed(Box<dyn StdError>),
-
     #[display(fmt = "blocking")]
     Blocking(BlockingError),
 
@@ -362,7 +352,6 @@ impl<E: StdError + 'static> StdError for EncoderError<E> {
     fn source(&self) -> Option<&(dyn StdError + 'static)> {
         match self {
             EncoderError::Body(err) => Some(err),
-            EncoderError::Boxed(err) => Some(&**err),
             EncoderError::Blocking(err) => Some(err),
             EncoderError::Io(err) => Some(err),
         }
diff --git a/actix-http/src/h1/dispatcher.rs b/actix-http/src/h1/dispatcher.rs
index 844bc61ea..163d84f5b 100644
--- a/actix-http/src/h1/dispatcher.rs
+++ b/actix-http/src/h1/dispatcher.rs
@@ -1077,7 +1077,7 @@ mod tests {
         fn_service(|req: Request| {
             let path = req.path().as_bytes();
             ready(Ok::<_, Error>(
-                Response::ok().set_body(AnyBody::from_slice(path)),
+                Response::ok().set_body(AnyBody::copy_from_slice(path)),
             ))
         })
     }
diff --git a/actix-http/src/response_builder.rs b/actix-http/src/response_builder.rs
index a1cb1a423..e934f94dc 100644
--- a/actix-http/src/response_builder.rs
+++ b/actix-http/src/response_builder.rs
@@ -262,7 +262,7 @@ impl ResponseBuilder {
         S: Stream<Item = Result<Bytes, E>> + 'static,
         E: Into<Box<dyn StdError>> + 'static,
     {
-        self.body(AnyBody::from_message(BodyStream::new(stream)))
+        self.body(AnyBody::new_boxed(BodyStream::new(stream)))
     }
 
     /// Generate response with an empty body.
diff --git a/awc/src/sender.rs b/awc/src/sender.rs
index fcd0c71af..02870aea9 100644
--- a/awc/src/sender.rs
+++ b/awc/src/sender.rs
@@ -9,7 +9,7 @@ use std::{
 };
 
 use actix_http::{
-    body::{Body, BodyStream},
+    body::{AnyBody, Body, BodyStream},
     http::{
         header::{self, HeaderMap, HeaderName, IntoHeaderValue},
         Error as HttpError,
@@ -286,7 +286,7 @@ impl RequestSender {
             response_decompress,
             timeout,
             config,
-            Body::from_message(BodyStream::new(stream)),
+            AnyBody::new_boxed(BodyStream::new(stream)),
         )
     }
 
diff --git a/src/dev.rs b/src/dev.rs
index 4fac207a7..27c206e70 100644
--- a/src/dev.rs
+++ b/src/dev.rs
@@ -14,7 +14,7 @@ pub use crate::types::form::UrlEncoded;
 pub use crate::types::json::JsonBody;
 pub use crate::types::readlines::Readlines;
 
-pub use actix_http::body::{AnyBody, Body, BodySize, MessageBody, ResponseBody, SizedStream};
+pub use actix_http::body::{AnyBody, Body, BodySize, MessageBody, SizedStream};
 
 #[cfg(feature = "__compress")]
 pub use actix_http::encoding::Decoder as Decompress;
diff --git a/src/middleware/compat.rs b/src/middleware/compat.rs
index 0a6256fe2..752e90f94 100644
--- a/src/middleware/compat.rs
+++ b/src/middleware/compat.rs
@@ -7,7 +7,7 @@ use std::{
     task::{Context, Poll},
 };
 
-use actix_http::body::{Body, MessageBody};
+use actix_http::body::{AnyBody, MessageBody};
 use actix_service::{Service, Transform};
 use futures_core::{future::LocalBoxFuture, ready};
 
@@ -124,7 +124,7 @@ where
     B::Error: Into<Box<dyn StdError + 'static>>,
 {
     fn map_body(self) -> ServiceResponse {
-        self.map_body(|_, body| Body::from_message(body))
+        self.map_body(|_, body| AnyBody::new_boxed(body))
     }
 }
 
diff --git a/src/middleware/compress.rs b/src/middleware/compress.rs
index 4854f4beb..3e85cb846 100644
--- a/src/middleware/compress.rs
+++ b/src/middleware/compress.rs
@@ -10,13 +10,14 @@ use std::{
 };
 
 use actix_http::{
-    body::{MessageBody, ResponseBody},
+    body::{AnyBody, MessageBody},
     encoding::Encoder,
     http::header::{ContentEncoding, ACCEPT_ENCODING},
     StatusCode,
 };
 use actix_service::{Service, Transform};
 use actix_utils::future::{ok, Either, Ready};
+use bytes::Bytes;
 use futures_core::ready;
 use once_cell::sync::Lazy;
 use pin_project::pin_project;
@@ -61,7 +62,7 @@ where
     B: MessageBody,
     S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = Error>,
 {
-    type Response = ServiceResponse<ResponseBody<Encoder<B>>>;
+    type Response = ServiceResponse<AnyBody<Encoder<B>>>;
     type Error = Error;
     type Transform = CompressMiddleware<S>;
     type InitError = ();
@@ -110,7 +111,7 @@ where
     S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = Error>,
     B: MessageBody,
 {
-    type Response = ServiceResponse<ResponseBody<Encoder<B>>>;
+    type Response = ServiceResponse<AnyBody<Encoder<B>>>;
     type Error = Error;
     type Future = Either<CompressResponse<S, B>, Ready<Result<Self::Response, Self::Error>>>;
 
@@ -142,15 +143,19 @@ where
 
             // There is an HTTP header but we cannot match what client as asked for
             Some(Err(_)) => {
-                let res = HttpResponse::with_body(
-                    StatusCode::NOT_ACCEPTABLE,
-                    SUPPORTED_ALGORITHM_NAMES.as_str(),
-                );
-                let enc = ContentEncoding::Identity;
+                let res = HttpResponse::new(StatusCode::NOT_ACCEPTABLE);
 
-                Either::right(ok(req.into_response(res.map_body(move |head, body| {
-                    Encoder::response(enc, head, ResponseBody::Other(body.into()))
-                }))))
+                let res: HttpResponse<AnyBody<Encoder<B>>> = res.map_body(move |head, _| {
+                    let body_bytes = Bytes::from(SUPPORTED_ALGORITHM_NAMES.as_bytes());
+
+                    Encoder::response(
+                        ContentEncoding::Identity,
+                        head,
+                        AnyBody::Bytes(body_bytes),
+                    )
+                });
+
+                Either::right(ok(req.into_response(res)))
             }
         }
     }
@@ -172,7 +177,7 @@ where
     B: MessageBody,
     S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = Error>,
 {
-    type Output = Result<ServiceResponse<ResponseBody<Encoder<B>>>, Error>;
+    type Output = Result<ServiceResponse<AnyBody<Encoder<B>>>, Error>;
 
     fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
         let this = self.project();
@@ -186,7 +191,7 @@ where
                 };
 
                 Poll::Ready(Ok(resp.map_body(move |head, body| {
-                    Encoder::response(enc, head, ResponseBody::Body(body))
+                    Encoder::response(enc, head, AnyBody::Body(body))
                 })))
             }
             Err(e) => Poll::Ready(Err(e)),
diff --git a/src/responder.rs b/src/responder.rs
index 005bff03e..4d2e97c36 100644
--- a/src/responder.rs
+++ b/src/responder.rs
@@ -232,7 +232,7 @@ pub(crate) mod tests {
     use bytes::{Bytes, BytesMut};
 
     use super::*;
-    use crate::dev::{Body, ResponseBody};
+    use crate::dev::AnyBody;
     use crate::http::{header::CONTENT_TYPE, HeaderValue, StatusCode};
     use crate::test::{init_service, TestRequest};
     use crate::{error, web, App};
@@ -264,13 +264,13 @@ pub(crate) mod tests {
 
     pub(crate) trait BodyTest {
         fn bin_ref(&self) -> &[u8];
-        fn body(&self) -> &Body;
+        fn body(&self) -> &AnyBody;
     }
 
     impl BodyTest for Body {
         fn bin_ref(&self) -> &[u8] {
             match self {
-                Body::Bytes(ref bin) => bin,
+                AnyBody::Bytes(ref bin) => bin,
                 _ => unreachable!("bug in test impl"),
             }
         }
@@ -279,27 +279,6 @@ pub(crate) mod tests {
         }
     }
 
-    impl BodyTest for ResponseBody<Body> {
-        fn bin_ref(&self) -> &[u8] {
-            match self {
-                ResponseBody::Body(ref b) => match b {
-                    Body::Bytes(ref bin) => bin,
-                    _ => unreachable!("bug in test impl"),
-                },
-                ResponseBody::Other(ref b) => match b {
-                    Body::Bytes(ref bin) => bin,
-                    _ => unreachable!("bug in test impl"),
-                },
-            }
-        }
-        fn body(&self) -> &Body {
-            match self {
-                ResponseBody::Body(ref b) => b,
-                ResponseBody::Other(ref b) => b,
-            }
-        }
-    }
-
     #[actix_rt::test]
     async fn test_responder() {
         let req = TestRequest::default().to_http_request();
diff --git a/src/response/builder.rs b/src/response/builder.rs
index f6099a019..e42d85f59 100644
--- a/src/response/builder.rs
+++ b/src/response/builder.rs
@@ -354,10 +354,10 @@ impl HttpResponseBuilder {
     #[inline]
     pub fn streaming<S, E>(&mut self, stream: S) -> HttpResponse
     where
-        S: Stream<Item = Result<Bytes, E>> + Unpin + 'static,
+        S: Stream<Item = Result<Bytes, E>> + 'static,
         E: Into<Box<dyn StdError>> + 'static,
     {
-        self.body(AnyBody::from_message(BodyStream::new(stream)))
+        self.body(AnyBody::new_boxed(BodyStream::new(stream)))
     }
 
     /// Set a json body and generate `Response`
diff --git a/src/response/response.rs b/src/response/response.rs
index 09515c839..46360e536 100644
--- a/src/response/response.rs
+++ b/src/response/response.rs
@@ -227,6 +227,9 @@ impl<B> HttpResponse<B> {
         }
     }
 
+    // TODO: into_body equivalent
+    // TODO: into_boxed_body
+
     /// Extract response body
     pub fn into_body(self) -> B {
         self.res.into_body()