ITarget::propagate Method
Visual Studio 2012
When overridden in a derived class, asynchronously passes a message from a source block to this target block.
virtual message_status propagate( _Inout_opt_ message<_Type> * _PMessage, _Inout_opt_ ISource<_Type> * _PSource ) = 0;
A message_status indication of what the target decided to do with the message.
The method throws an invalid_argument exception if either the _PMessage or _PSource parameter is NULL.