onSend method

@override Msg? onSend(Msg msg)

Called for each message before it is queued.

Return the same message to keep it, a modified message to transform it, or null to drop it.

Implementation

@override
Msg? onSend(Msg msg) {
  _queuedMessageCount++;

  // Let inner interceptor transform/drop the message first.
  final innerResult = inner?.onSend(msg);
  // If the inner interceptor exists and dropped the message, propagate.
  if (inner != null && innerResult == null) return null;
  final transformed = innerResult ?? msg;

  // Begin Timeline span for message processing.
  if (enableTimeline) {
    _currentMsg = transformed;
    _messageSw
      ..reset()
      ..start();
    dev.Timeline.startSync(
      'artisanal.message',
      arguments: <String, String>{
        'type': transformed.runtimeType.toString(),
        'summary': _summarizeMsg(transformed),
      },
    );
  }

  return transformed;
}