improve body size docs

actix-http/src/body.rs

@@ -15,13 +15,39 @@ use crate::error::Error;
 /// Body size hint.
 #[derive(Debug, PartialEq, Copy, Clone)]
 pub enum BodySize {
+    /// Absence of body can be assumed from method or status code.
+    ///
+    /// Will skip writing Content-Length header.
     None,
+
+    /// Zero size body.
+    ///
+    /// Will write `Content-Length: 0` header.
     Empty,
+
+    /// Known size body.
+    ///
+    /// Will write `Content-Length: N` header. `Sized(0)` is treated the same as `Empty`.
     Sized(u64),
+
+    /// Unknown size body.
+    ///
+    /// Will not write Content-Length header. Can be used with chunked Transfer-Encoding.
     Stream,
 }
 
 impl BodySize {
+    /// Returns true if size hint indicates no or empty body.
+    ///
+    /// ```
+    /// # use actix_http::body::BodySize;
+    /// assert!(BodySize::None.is_eof());
+    /// assert!(BodySize::Empty.is_eof());
+    /// assert!(BodySize::Sized(0).is_eof());
+    ///
+    /// assert!(!BodySize::Sized(64).is_eof());
+    /// assert!(!BodySize::Stream.is_eof());
+    /// ```
     pub fn is_eof(&self) -> bool {
         matches!(self, BodySize::None | BodySize::Empty | BodySize::Sized(0))
     }

actix-http/src/client/h2proto.rs

@@ -36,6 +36,7 @@ where
     B: MessageBody,
 {
     trace!("Sending client request: {:?} {:?}", head, body.size());
+
     let head_req = head.as_ref().method == Method::HEAD;
     let length = body.size();
     let eof = matches!(

actix-http/src/encoding/encoder.rs

@@ -78,6 +78,7 @@ impl<B: MessageBody> Encoder<B> {
                 });
             }
         }
+
         ResponseBody::Body(Encoder {
             body,
             eof: false,