Failed example:
    counter.reschedule(
        timedelta(microseconds=1)
    ); wait_until(lambda: run_count==5)
Expected:
    datetime.timedelta(0, 0, 1)
    run() call 3 running ... in <RepositoryThread(RepositoryPoolThread...)>
    run() call 4 running ... in <RepositoryThread(RepositoryPoolThread...)>
    run() call 5 running ... in <RepositoryThread(RepositoryPoolThread...)>
Got:
    run() call 3 running <PeriodicTask (new): counter b5495720-0410-11dc-b8ea-00
1346a711f0> in <RepositoryThread(RepositoryPoolThread-54071984-3, started daemon
)>
    datetime.timedelta(0, 0, 1)
    run() call 4 running <PeriodicTask (new): counter b5495720-0410-11dc-b8ea-00
1346a711f0> in <RepositoryThread(RepositoryPoolThread-54071984-1, started daemon
)>
    run() call 5 running <PeriodicTask (new): counter b5495720-0410-11dc-b8ea-00
1346a711f0> in <RepositoryThread(RepositoryPoolThread-54071984-2, started daemon
)>