Documentation for this section has not yet been entered.
Returns the number of registered callbacks. Note that the number of registered callbacks may differ from the value returned by RemoteCallbackList.BeginBroadcast since the former returns the number of callbacks registered at the time of the call and the second the number of callback to which the broadcast will be delivered.
This function is useful to decide whether to schedule a broadcast if this requires doing some work which otherwise would not be performed.