// Called from MeterListener.EnableMeasurementEvents
internal void EnableMeasurement(ListenerSubscription subscription)
{
while (!_subscriptions.AddIfNotExist(subscription, (s1, s2) => object.ReferenceEquals(s1.Listener, s2.Listener)))
{
ListenerSubscription oldSubscription = _subscriptions.Remove(subscription, (s1, s2) => object.ReferenceEquals(s1.Listener, s2.Listener));
if (object.ReferenceEquals(oldSubscription.Listener, subscription.Listener))
{
oldSubscription.Listener.MeasurementsCompleted?.Invoke(this, oldSubscription.State);
}
}
}
// Called from MeterListener.EnableMeasurementEvents
internal object?EnableMeasurement(ListenerSubscription subscription, out bool oldStateStored)
{
oldStateStored = false;
if (!_subscriptions.AddIfNotExist(subscription, (s1, s2) => object.ReferenceEquals(s1.Listener, s2.Listener)))
{
ListenerSubscription oldSubscription = _subscriptions.Remove(subscription, (s1, s2) => object.ReferenceEquals(s1.Listener, s2.Listener));
_subscriptions.AddIfNotExist(subscription, (s1, s2) => object.ReferenceEquals(s1.Listener, s2.Listener));
oldStateStored = object.ReferenceEquals(oldSubscription.Listener, subscription.Listener);
return(oldSubscription.State);
}
return(false);
}