Trait StreamingBody
pub trait StreamingBody {
type Data: Buf;
type Error;
// Required method
fn poll_frame(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Option<Result<Frame<Self::Data>, Self::Error>>>;
// Provided methods
fn is_end_stream(&self) -> bool { ... }
fn size_hint(&self) -> SizeHint { ... }
}Available on crate features
http and std only.Expand description
Trait representing a streaming body of a Request or Response.
Individual frames are streamed via the poll_frame function, which asynchronously yields
instances of Frame<Data>.
Frames can contain a data buffer of type Self::Data. Frames can also contain an optional
set of trailers used to finalize the request/response exchange. This is mostly used when using
the HTTP/2.0 protocol.
The size_hint function provides insight into the total number of bytes that will be streamed.
Required Associated Types§
Required Methods§
fn poll_frame(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Option<Result<Frame<Self::Data>, Self::Error>>>
fn poll_frame( self: Pin<&mut Self>, cx: &mut Context<'_>, ) -> Poll<Option<Result<Frame<Self::Data>, Self::Error>>>
Attempt to pull out the next frame of this stream.
§Return value
This function returns:
Poll::Pendingif the next frame is not ready yet.Poll::Ready(Some(Ok(frame)))when the next frame is available.Poll::Ready(Some(Err(error)))when an error has been reached.Poll::Ready(None)means that all of the frames in this stream have been returned, and that the end of the stream has been reached.
If Poll::Ready(Some(Err(error))) is returned, this body should be discarded.
Once the end of the stream is reached, implementations should continue to return
Poll::Ready(None).
Provided Methods§
fn is_end_stream(&self) -> bool
fn is_end_stream(&self) -> bool
A hint that may return true when the end of stream has been reached.
An end of stream means that poll_frame will return None.
A return value of false does not guarantee that a value will be
returned from poll_frame. Combinators or other implementations may
not be able to know the end of stream has been reached for this hint.
Returning true allows consumers of this body to optimize, such as not
calling poll_frame again.
Dyn Compatibility§
This trait is dyn compatible.
In older versions of Rust, dyn compatibility was called "object safety".