Trait ObserverHandle 

pub trait ObserverHandle: Send {
    // Required methods
    fn recv(
        &mut self,
    ) -> Pin<Box<dyn Future<Output = Result<ProgressEvent, ObserverRecvError>> + Send + '_>>;
    fn try_recv(&mut self) -> Result<ProgressEvent, ObserverRecvError>;
    fn close(self: Box<Self>);
}

Handle returned by crate::execution::ExecutionService::observe.

Wraps a tokio::sync::broadcast::Receiver<ProgressEvent> (provided by the engine layer, Subtask 2). Multiple handles may exist concurrently; each receives the full event stream independently. When the session’s broadcast sender is dropped (session terminates), recv() returns Err(ObserverRecvError::Closed).

This is a trait to allow the engine layer (Subtask 2) to provide a concrete BroadcastObserverHandle struct without a circular dependency on core.

Required Methods

fn recv( &mut self, ) -> Pin<Box<dyn Future<Output = Result<ProgressEvent, ObserverRecvError>> + Send + '_>>

Receive the next event, waiting asynchronously.

Returns Err(ObserverRecvError::Closed) when the broadcast sender is dropped (session terminated). Returns Err(ObserverRecvError::Lagged(n)) when the receiver fell behind and n events were skipped; subsequent calls continue from the latest available event.

fn try_recv(&mut self) -> Result<ProgressEvent, ObserverRecvError>

Non-blocking receive. Returns an event if one is immediately available, Err(ObserverRecvError::Closed) if the sender is gone, or Err(ObserverRecvError::Lagged(n)) on a lag event.

Callers should treat Err variants consistently with Self::recv.

fn close(self: Box<Self>)

Consume and close this handle. After calling close the handle is dropped and no further events can be received.

Implementors