Stream

A Stream is a handle to a background strand created by stream. Unlike a plain Strand, a Stream has input and output channels wired up automatically. It implements Iterable for its output side and Sinkable for its input side.

Fields

done

A read-only boolean indicating whether the strand has completed execution.

Methods

join()

Closes both channels, then waits for the strand to complete. If the strand exited normally, returns its result. If the strand exited with an error, re-raises it.

Closing the channels before waiting prevents deadlock when the strand is blocked waiting for input or waiting for a consumer to read its output.

wait()

Waits for the strand to complete. Unlike join(), this method does not close the channels, does not return the strand's result, and does not re-raise any error.

cancel()

Requests cancellation of the strand, causing a Canceled error to be raised at the strand's next suspension point.

Error Propagation

When the stream strand exits with an error:

• s.iter().next() re-raises the error once the output channel is exhausted (instead of raising a generic IterStop error).
• s.sink().put <item> still raises SinkStop when the input channel is closed.
• s.join() re-raises the strand error directly.

This means consumer-side errors still surface naturally from the output receiver, while producer-side callers continue to see ordinary sink shutdown.