[Optimization] Try shared memory instead of socket

[dylanebert]

Socket is a major bottleneck, may be possible to try shared memory instead:

• https://docs.python.org/3/library/multiprocessing.shared_memory.html
• https://answers.unity.com/questions/1249732/how-to-use-shared-memory-in-unity.html

[vwxyzjn]

Related thread https://github.com/Unity-Technologies/ml-agents/issues/3958. Maybe https://github.com/pythonnet/pythonnet can help with shared memory.