Struct RequestCancellationHandle 

pub struct RequestCancellationHandle { /* private fields */ }

Explicit cancellation control for one outgoing request.

Obtain this handle from PreparedRequest::cancellation_handle or SentRequest::cancellation_handle before consuming the request. It retains neither the response consumer nor application callback, so cancellation can be requested without discarding the eventual response. It does not keep the connection driver or response consumer alive, or abort local callback work.

Clones share the request’s cancellation state with SentRequest::cancel, forwarded cancellation, and request-drop automatic cancellation. At most one cancellation notification is attempted, with the original peer and proxy wrapping. Dropping this handle neither cancels the request nor disables its automatic cancellation.

Cancellation before publication is a no-op and is not remembered for later publication. A call racing publication may also be a no-op; call after the publishing method returns to target a pending request. Once the SDK routes a response or fails the request, subsequent cancellation calls are no-ops, even if its callback has not yet run. Detaching the request suppresses only automatic cancellation; retained handles can still explicitly cancel it.

This controls outgoing requests, unlike RequestCancellation, which observes a peer’s cancellation of an incoming request.

Implementations

impl RequestCancellationHandle

pub fn cancel(&self) -> Result<(), Error>

Ask the peer to cancel this request without discarding its response.

Cancellation is cooperative: the peer may respond normally or with a cancellation error. Repeated calls, including calls through other clones or the original request, return Ok(()) without sending another notification. Calls before publication or after settlement are no-ops. An attempt begun before settlement may still enqueue afterward.

Ok(()) means this call encountered no immediate error, not that a notification was sent or the peer stopped work. This method does not wait for transmission or acknowledgment.

Errors

Only the call that attempts to send reports serialization or enqueue failure. A failed send is not retried by later cancellation calls.

Trait Implementations

impl Clone for RequestCancellationHandle

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for RequestCancellationHandle

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

Formats the value using the given formatter.