WebSocket (RPC) streaming for `assistantMessage` and `describe`

[samchon]

To change RPC type and refactor websocket logic, support streaming of above types

[rushichavda]

Hey @samchon - I have given a shot at this, i think i can have this implemented, can you assign this to me. Thanks!!

[samchon]

Already implemented from other project, so will reflect to here soon. Thanks for suggestion.