Let QuicSession's various write methods set transmission type.
gfe-relnote: protected by gfe2_reloadable_flag_quic_write_with_transmission.
PiperOrigin-RevId: 300418485
Change-Id: Ibd56987aa9461017040f800960651983f15e12b3
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.