s2n-quic server fails resumption interop test with neqo client

[goatgoose]

Problem:

The resumption interop test has recently started failing with the neqo client and s2n-quic server. neqo has released a fix related to this issue (mozilla/neqo#1837), but the interop test is still failing with neqo and s2n-quic.

Solution:

We should investigate the cause of this test failure. If the issue can be addressed in s2n-quic, we should resolve it and revert #2191 to enforce the resumption test with neqo and s2n-quic in CI.

[mxinden]

Sorry for the trouble here @goatgoose.

mozilla/neqo#1837 fixed the issue.

The resumption testcase using neqo client s2n-quic server is no longer failing. See e.g. recent CI run:

mozilla/neqo#1857 (comment)

The neqo-qns Docker image is published nightly, thus reverting #2191 should succeed now.

[goatgoose]

Hi @mxinden, it appears that even after the mozilla/neqo#1837 fix, the neqo client and s2n-quic server still fail the resumption test. From mozilla/neqo#1857 (comment):

Failed Interop Tests
neqo-latest vs. s2n-quic: R A

However, looking at the interop runner, it seems like mozilla/neqo#1837 fixed the issue for all implementations except for s2n-quic:

So we plan to investigate this to see if s2n-quic is causing this issue.