Literal based overloads for asyncio transport

[kumaraditya303]

Asyncio transport get_extra_info has defined value as it's argument so it can be overloaded with Literal see https://docs.python.org/3/library/asyncio-protocol.html#asyncio.BaseTransport.get_extra_info

[A5rocks]

I do not think it can, as it seems that this is a base class:

name is a string representing the piece of transport-specific information to get.

- the docs