When calling PGC_SetAndActivateControl via ZeroMQ from acq4/WSE and this asserts out, it is not obvious if the call is from within MIES or came from the outside. The experienced dev might notice that the IPF stacktrace starts with PGC and that means it is from ZeroMQ's CallFunction, as nobody is calling it from the command line.

We should enhance the stacktrace to be clear that this came from the ZeroMQ-XOP. And also include the zeromq socket router id (formerly called identify).

This can be either done with calling a labelling function first or a global string.