Introducing IOStream protocol and adding support for websockets (#1551)

* Introducing IOStream

* bug fixing

* polishing

* refactoring

* refactoring

* refactoring

* wip: async tests

* websockets added

* wip

* merge with main

* notebook added

* FastAPI example added

* wip

* merge

* getter/setter to iostream added

* website/blog/2024-03-03-AutoGen-Update/img/dalle_gpt4v.png: convert to Git LFS

* website/blog/2024-03-03-AutoGen-Update/img/gaia.png: convert to Git LFS

* website/blog/2024-03-03-AutoGen-Update/img/teach.png: convert to Git LFS

* add SSL support

* wip

* wip

* exception handling added to on_connect()

* refactoring: default iostream is being set in a context manager

* test fix

* polishing

* polishing

* polishing

* fixed bug with new thread

* polishing

* a bit of refactoring and docs added

* notebook added to docs

* type checking added to CI

* CI fix

* CI fix

* CI fix

* polishing

* obsolete todo comment removed

* fixed precommit error

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Co-authored-by: Eric Zhu <ekzhu@users.noreply.github.com>