Pierre-Yves David <pierre-yves.david@octobus.net> [Mon, 31 Jan 2022 19:28:58 +0100] rev 48676
transaction: add a way to know a transaction has been finalized
This will be useful to fix the timing of the branchmap on disk caching.
Differential Revision: https://phab.mercurial-scm.org/D12127