notifyOne method

void notifyOne()

Wake up exactly one waiter, or store one permit if no waiters.

If there are waiting tasks, wakes the first one. If no tasks are waiting, stores a permit that will be consumed by the next notified call.

Use cases:

  • Single resource became available
  • One-time configuration change
  • Single task completion notification

Example:

// Resource pool - notify when one resource is free
void releaseResource() {
  returnResourceToPool();
  resourceAvailable.notifyOne(); // Wake one waiting task
}

Implementation

void notifyOne() {
  if (_closed) return;
  _epoch++;
  for (var i = 0; i < _waiters.length; i++) {
    final c = _waiters.removeAt(0);
    if (!c.isCompleted) {
      c.complete();
      return;
    }
  }
  _permits++;
}