#include <SimG4Core/Notification/interface/Signaler.h>
Description: Manages a particular signal of the SimActivityRegistry
Usage: This is an internal detail of how the SimActivityRegistry does its job.
Having Signaler inherit frmo Observer<const T*> allows one Signaler to forward its signal to another Signaler.
All connected Observers are required to have a lifetime greater than the Signaler to which they are attached.