Daemon thread factory used by the monitor executors.
This factory creates all new threads used by an Executor in the same ThreadGroup.
If there is a SecurityManager, it uses the group of System.getSecurityManager(), else the group
of the thread instantiating this DaemonThreadFactory. Each new thread is created as a daemon thread
with priority Thread.NORM_PRIORITY. New threads have names accessible via Thread.getName()
of "<pool-name> Pool [Thread-M]", where M is the sequence number of the thread created by this factory.