Struct SendStream 

pub struct SendStream<T> { /* private fields */ }

A stream of messages to the peer.

On the client, the request messages of a client-streaming or a bidi call. On the server, the response messages of a server-streaming or a bidi call.

The stream is shared, clones send on the same stream. Messages are sent one at a time, send() waits for the one in progress. Concurrent sends queue in the order their futures are first polled. Dropping the last clone or calling close() ends the stream, the client half-closes its request then. The server ends the stream when the handler returns.

Implementations

impl<T> SendStream<T>

pub fn new() -> Self

Creates a stream for a client-streaming call.

Pass it to the call, messages are sent once the call is opened, send() waits until then.

pub fn poll_ready(&self, cx: &Context<'_>) -> Poll<Result<(), StreamError>>

Checks if a message can be sent.

Ready once the stream is open and no message is being sent, fails if the stream is closed. Does not wait for flow-control capacity, send() does. Readiness does not reserve a turn to send.

pub async fn ready(&self) -> Result<(), StreamError>

Waits until a message can be sent, see poll_ready().

pub fn close(&self)

Ends the stream, no more messages are sent.

A message being sent is completed first. On the server the stream ends when the handler returns.

pub fn cancel(&self)

Cancels the call, the h2 stream is reset with CANCEL.

On the client the response stream, or the reply of a client-streaming call, fails with ClientError::StreamFailed and CANCELLED.

pub fn is_closed(&self) -> bool

Checks if the stream is closed, no more messages can be sent.

pub fn header(&self, name: HeaderName, value: HeaderValue) -> bool

Adds a response header, server side only.

Returns false if the headers are sent already, with the first message, or on the client.

Headers exceeding the peer’s limit reset the call with INTERNAL_ERROR when the response starts.

pub fn trailer(&self, name: HeaderName, value: HeaderValue)

Adds a response trailer, server side only.

The trailers are sent when the handler returns.

impl<T: Message> SendStream<T>

pub async fn send(&self, msg: &T) -> Result<(), StreamError>

Sends a message.

Waits until the stream is open, until a message being sent is completed, and for flow-control capacity. A message over the size limit fails with StreamError::Status and is not sent, the stream stays usable. Other errors end the stream.

Dropping the future while it waits for its turn removes it from the queue without cancelling the call. Dropping the future while the message is written cancels the call.

Trait Implementations

impl<T> Clone for SendStream<T>

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T> Debug for SendStream<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T> Default for SendStream<T>

fn default() -> Self

Returns the “default value” for a type.

impl<T> Drop for SendStream<T>

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.