code: protected void ensureEventSource(UUID eventSource, Event event) {
  		if (event.getSource() == null) {
  			if (eventSource != null) {
  				event.setSource(new Address(getSpaceID(), eventSource));
  			} else {
  				throw new AssertionError("Every event must have a source"); //$NON-NLS-1$
  			}
  		}
  	}
docs: Ensure that the given event has a source.
  
  @param eventSource the source of the event.
  @param event the event to emit.
  @since 2.0.6.0