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

• 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).

まず、読み取りが一時停止されている間のアクセスに焦点を当てて、uvloop の TCP transport と vanilla asyncio の transport._sock の動作を比較します。報告された MSG_PEEK のユースケースについて、uvloop を介して一時停止中のソケットのバイト列を検査するサポートされた方法があり、issue の再現手順の詳細に照らして動作が確認できれば完了です。