Major Description
This reactor bug :
https://github.com/reactor/reactor-core/issues/1941
is the source of instability in our tests, as in the case of a first failing first publisher in a merge operation, its error would not be propagated and the result of the merge will be a successful Publisher instead of the expected failing one.
This behavior is reproductible in :
ConsistencyTasksIntegrationTest.shouldRecomputeMailboxCounters
Where the merge operation in CassandraMessageIdMapper.insertIds is impacted by this bug.
This bug should not be a real problem in real usage as it fails only when the failure is immediate. Which should not be the case with Publisher doing IOs in production usage.
So we will add a delay in the throwing behavior in the integration tests and wait for this bug to be fixed in reactor.