Add a OnCoalescedPacketSent to QuicConnectionDebugVisitor. This will used for net-log in chromium.
gfe-relnote: n/a (debug only change)
PiperOrigin-RevId: 301652636
Change-Id: Ib899939a4def1555e04d561fcddbbf419f3efd03
QUICHE (QUIC, Http/2, Etc) is Google‘s implementation of QUIC and related protocols. It powers Chromium as well as Google’s QUIC servers and some other projects.