| Name | Type | Description |
|---|---|---|
event* | ProtocolEvent | The protocol event to observe. |
Handle an event on the async lane.
The mux awaits this before dispatching to the next transformer,
so a slow aprocess serializes the pipeline. Use it only when
a later transformer — or a consumer reading the event
synchronously — must see the result of the async work (e.g.
PII redaction that mutates event in place).
The default delegates to process, so purely-sync transformers
run unchanged under astream().
