message: refactor(body): improve Debug format of Body
diff: @@ -343,7 +343,21 @@ impl Stream for Body {
  impl fmt::Debug for Body {
  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
  - f.debug_struct("Body").finish()
  + #[derive(Debug)]
  + struct Streaming;
  + #[derive(Debug)]
  + struct Empty;
  + #[derive(Debug)]
  + struct Once<'a>(&'a Chunk);
  +
  + let mut builder = f.debug_tuple("Body");
  + match self.kind {
  + Kind::Once(None) => builder.field(&Empty),
  + Kind::Once(Some(ref chunk)) => builder.field(&Once(chunk)),
  + _ => builder.field(&Streaming),
  + };
  +
  + builder.finish()
  }
  }
  