Commit Message: make HTTP/3 upstream sends 0-RTT (early data) requests if it has cached 0-RTT credentials. Add a config knob in RouteAction to specify which request can be sent over early data, which by default are HTTP safe methods.
Risk Level: high, changes to conn pool behavior though should only take effect for h3 pool
Testing: added h3 upstream integration tests.
Docs Changes: N/A
Release Notes: changes to docs/root/version_history/current.rst
Platform Specific Features: N/A
Runtime guard: envoy.reloadable_features.http3_sends_early_data
Fixes#18715, #19542
Signed-off-by: Dan Zhang <danzh@google.com>
Signed-off-by: Dan Zhang <danzh@google.com>
Mirrored from https://github.com/envoyproxy/envoy @ 8ce13d75a982ddd347db5a333a4bb080922f7514