Mixin for being informed about reception of HCI Events from the HCI that are associated with sending ACL or Synchronous data to the HCI. This should be implemented by the Stack/HCI Facade.

This interface is used as a way of passing the following unsolicited data events: Number_Of_Completed_Packets Event Flush_Occurred Event Data_Buffer_Overflow Event QoS_Violation Event Note that events that seem data related but are in fact the result of a command (e.g. QoS Setup Command) do not follow the path described above and go to MHCICommandEventObserver instead. MHCICommandEventObserver