When Vim is inactive, I can attach a function in a CursorHold autocmd event which would consists of loop that reads from the resource object and sleeps for a small interval after that. As the external program/socket connection is running in separate process, reading from it is not resource sensitive so it should not block Vim entirely.

BTW there is a plugin called CoVim https://github.com/FredKSchott/CoVim that implements pair-programming feature using default built-in Python binding.