This contact is used to process signals of internal system.
In asynchronous execution the resulting signal should come
at the same level of "call stack". However as far as we usually get the signal asynchronously
it is processed at top level. So in order to run it in inside the subsystem,
we package asynchronous result into
Signal(SubsystemSpecialContact, SubsystemDirectSignal( name, actual resulting signal))
This contact is used to process signals of internal system.
In asynchronous execution the resulting signal should come at the same level of "call stack". However as far as we usually get the signal asynchronously it is processed at top level. So in order to run it in inside the subsystem, we package asynchronous result into Signal(SubsystemSpecialContact, SubsystemDirectSignal( name, actual resulting signal))