Fix unit test races (carry #48)

[thaJeztah]

carries: https://github.com/moby/spdystream/pull/48 closes https://github.com/moby/spdystream/pull/48

[thaJeztah]

CI failure is unrelated; will be fixed by https://github.com/moby/spdystream/pull/90

[thaJeztah]

@dims PTAL 🤗

[dims]

hmm, 90 needs one more approval before we can land that and make this go green here

[thaJeztah]

hmm, 90 needs one more approval before we can land that and make this go green here

I, erm, went slightly ahead and got that one in to fix CI 😅 😇

@dmcgowan ptal

[thaJeztah]

FWIW; I just noticed that https://github.com/moby/spdystream/pull/86 also has a fix for this, so we could choose to take that one as well (I guess either approach would work)

[dmcgowan]

Either is fine, #86 is a bit bigger and think it needs some validation

[aojea]

/lgtm

I'm going to close #86 since it should no longer needed

[thaJeztah]

@dmcgowan I saw you merged another PR; I rebased this one again to get a fresh run of CI 👍