Can't peek at paused bytes (socket behind TCPTransport unavailable)

[rwarren]

• uvloop version: 0.14.0
• Python version: 3.8.2
• Platform: linux
• Can you reproduce the bug with PYTHONASYNCIODEBUG in env?: n/a (this is an api thing)
• Does uvloop behave differently from vanilla asyncio? How?:
  • vanilla asyncio: the underlying socket is available in transport._sock for consenting coders aware of the risks using "private" members
  • uvloop: the underlying socket is not available to python at all (or at least I can't find it via introspection)

FWIW, one reason I'm running into this right now is that I have a case where the transport is paused for reading (transport.pause_reading()), but I would still like to peek at the bytes with sock.recv(n, socket.MSG_PEEK).

[1st1]

vanilla asyncio: the underlying socket is available in transport._sock for consenting coders aware of the risks using "private" members

This won't be the case soon, as asyncio adopts the same proxy-socket object design choice that uvloop made.

Ideally we need to add new API to asyncio for peeking.