plimsoll v0.17.6

A session pool's memory reservation is given back exactly once, whatever the order of a failed pool start and Drain, and the docs state the small-pool warm guarantee for the sessions it covers.

Sessions

• The memory budget stays whole when Drain races a pool start. WithAdmission reserves a session pool's memory before the provider starts the pool. If Drain finished while that start was still inside the provider, and the provider then refused the start, v0.17.4 and v0.17.5 gave the reservation back twice, so the budget admitted a pool's worth of runs more than it holds. Each reservation is now given back once, by whichever of the failed start and Drain comes first. Only an embedder that kept serving runs after Drain could be affected.
• The small-pool guarantee is stated for the sessions it covers. A pool of 4 or fewer warms every language in every waiting container, so a session handed one finds its languages warm. Opens that find no container waiting, as a burst larger than the pool can, create their containers as they would without a pool. The v0.17.5 notes said every session. docs/sessions.md, "A warm pool".

Clients

• @plimsollmark/client and the Python client are at 0.17.6, unchanged apart from the version.