Re #6811. Remove unused (apart from in the test) method.
Re #6811. Minor tidy-ups.
Re #6811. Remove isRunningAsync() method - it is not used anywhere.
Re #6811. Thread-safety around the running & cancel flags.

Also some const-correctness.
Re #6811. Const-correctness.
Merge branch 'feature/6811_monitorlivedata_races' into develop