expectVantageEventSourceIsBroadcast function

void expectVantageEventSourceIsBroadcast(
  1. EventSource source
)

Asserts source exposes a broadcast stream. The host holds one subscription and panels may hold more, so a single-subscription controller would make the second listener throw at runtime.

Implementation

void expectVantageEventSourceIsBroadcast(EventSource source) {
  expect(
    source.events.isBroadcast,
    isTrue,
    reason: 'EventSource.events must be a broadcast stream: use '
        'StreamController.broadcast(). The host subscribes once and panels may '
        'subscribe too.',
  );
}