Allow QuicSession::WritevData() to write data at a specified encryption level.
gfe-relnote: protected by gfe2_reloadable_flag_quic_writevdata_at_level
PiperOrigin-RevId: 297697074
Change-Id: Ib4e5d860f22f506f36db76f4f8ee1c1e406f6a20
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.