This CL implements the backend server behavior described in Section 7.2
of draft-ietf-tls-esni-09.
Bug: 275
Change-Id: I2e162673ce564db0cb75fc9b71ef11ed15037f4b
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/43924
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: David Benjamin <davidben@google.com>