New mechanism description of fsm in actor .

[kotbegemot]

Motivation:

Next stage is development of coroutine support from standard C++ 20.
coroutine will be an event loop for actor.
Actor performance depends on speed of switching states
Actor allocations should be nearby.

Small Trouble:

1. actor performance drops when switching the coroutine.
   problem is related to std::unordered_map as hashmap.
   hashmap is not adapted to work with coroutine

2. actor-zeta refuses to use operator new().
   actor-zeta will switch to using a memory_resource

Research problem :
https://github.com/efficient/libcuckoo
https://www.youtube.com/watch?v=j9tlJAqMV7U
http://www.vldb.org/pvldb/vol11/p1702-jonathan.pdf
https://turingcompl33t.github.io/Coroutine-Map/