answerSubscribe property
Answers subscribeOnUpdates. Unset opens a stream that never emits and
never ends.
Silence rather than a throw, unlike the reads: a channel is opened by the framework when a subscribing widget mounts, not by the test, so failing here would break tests about something else entirely with a message about an operation their author never wrote. It never ends either — a closed channel reads as the server having dropped it, and the framework would leave a reconnect timer pending for the test to trip over.
Implementation
Stream<SerializableModel> Function(String channel)? answerSubscribe;