This change sets the removeOnCancelPolicy on the SockJS
ScheduledThreadPoolExecutor to true. This ensures that cancelled
tasks are removed immediately to avoid the "unbounded retention
of cancelled tasks" that is mentioned in the Javadoc of
ScheduledThreadPoolExecutor:
"By default, such a cancelled task is not automatically removed from
the work queue until its delay elapses. While this enables further
inspection and monitoring, it may also cause unbounded retention of
cancelled tasks. To avoid this, set setRemoveOnCancelPolicy to true,
which causes tasks to be immediately removed from the work queue at
time of cancellation."
Issue: SPR-11918
5d2e6f6d4c