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# Refs - extracted from https://github.com/neondatabase/neon/pull/9353 # Problem Before this PR, when task_mgr shutdown is signalled, e.g. during pageserver shutdown or Tenant shutdown, initial logical size calculation stops polling and drops the future that represents the calculation. This is against the current policy that we poll all futures to completion. This became apparent during development of concurrent IO which warns if we drop a `Timeline::get_vectored` future that still has in-flight IOs. We may revise the policy in the future, but, right now initial logical size calculation is the only part of the codebase that doesn't adhere to the policy, so let's fix it. ## Code Changes - make sensitive exclusively to `Timeline::cancel` - This should be sufficient for all cases of shutdowns; the sensitivity to task_mgr shutdown is unnecessary. - this broke the various cancel tests in `test_timeline_size.py`, e.g., `test_timeline_initial_logical_size_calculation_cancellation` - the tests would time out because the await point was not sensitive to cancellation - to fix this, refactor `pausable_failpoint` so that it accepts a cancellation token - side note: we _really_ should write our own failpoint library; maybe after we get heap-allocated RequestContext, we can plumb failpoints through there.