A protocol for delivering events to a target.

By default, this protocol is implemented for:

• Tuple - Interpreted as a {module, function, args} tuple. The function is called with the event type and ID given as the first and second argument.
• PID - A message in the form of {:event, event_type, event_id} is sent to the PID.
• Function - The function is called with the arguments event_type and event_id