tree f836c7da9ce38bcc1ffe3301917e4c4f1e758aa0
parent e0b0f6de6c000f1f69fd2258f22a8da1c5f8b2de
author wub <wub@google.com> 1788540306 -0700
committer Copybara-Service <copybara-worker@google.com> 1788540398 -0700

Add metrics to debug b/537474108.

Changes include:
- Add `/gfe/gfe2/quic/more_to_read_after_epoll_in` counter: Increments
  when an EPOLLIN event finishes but the QUIC socket is not drained.
- Add `/gfe/gfe2/quic/has_buffered_chlos_after_epoll_in` counter: Increments
  when an EPOLLIN event finishes but there are some CHLOs buffered.
- Add `/gfe/gfe2/quic/buffered_session_queue_time` distribution: Tracks
  the duration (in ms) from the earliest buffered packet's receipt time
  to the actual session creation. This is recorded in the new
  `QuicDispatcher::OnNewSessionCreated` virtual method.
- Add `/gfe/gfe2/quic/buffered_sessions` distribution: Exports the
  number of buffered sessions (both total and without full CHLO)
  after a QUIC packet is processed.

PiperOrigin-RevId: 976362820