Completes 835fc08c, which fixed the harness's DisposeAsync but left StopNodeBAsync
calling NodeB.DisposeAsync() directly — despite that commit's own message naming
it as carrying the same bug. Caught by re-reading the code rather than trusting
the commit message.
This one is not just about memory. IHost.DisposeAsync never invokes
IHostedService.StopAsync, so CoordinatedShutdown never runs and node B never
performs a graceful Cluster.Leave. Node A instead notices only when the failure
detector times the member out — a slower and materially different path from the
graceful leave the failover tests are written to exercise. The doc comment
asserted the opposite ("shuts down node B via DisposeAsync, which runs
CoordinatedShutdown"); it now says what actually happens and why.
Verified: the three failover suites that call it pass (5/5), and the project is
unchanged at 194 passed with only the AbCip fixture failure, which needs a docker
fixture that is not running.
Also checked the sibling harness while here: LocalDbPairHarness already stops each
host before disposing it, so it needed nothing.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Joseph Doherty
8838e92d0a