Struct Subscription

pub struct Subscription<S, M, I>
where
    M: Message,
{ /* private fields */ }

A subscription associated with a MessageStream that allows for sending and receiving control messages over it.

Notes

• in order for any send or read operations to resolve, the associated MessageStream stream needs to be polled; that is necessary because this operation expects a control message response and that control message comes through the regular stream.

Implementations

impl<S, M, I> Subscription<S, M, I>

where S: Sink<I> + Unpin, M: Message,

pub async fn send( &mut self, item: I, ) -> Result<Option<Result<M::ControlMessage, ()>>, S::Error>

Send a message over the internal control channel and wait a control message response.

The method returns the following errors:

• Err(..) when the sink failed to send an item
• Ok(None) when the message stream got closed
• Ok(Some(Err(()))) when message classification reported an error; the actual error still manifests through the message stream

pub async fn read(&mut self) -> Option<Result<M::ControlMessage, ()>>

Wait for a control message to arrive.

Trait Implementations

impl<S: Debug, M, I: Debug> Debug for Subscription<S, M, I>

where M: Message + Debug, M::ControlMessage: Debug,

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

Formats the value using the given formatter.