doing this unblocks incoming metrics while waiting for a flush to take place. we have to create a semaphore so that we can 'skip' flushes that try to run while a flush is already running. closes #2262
doing this unblocks incoming metrics while waiting for a flush to take place. we have to create a semaphore so that we can 'skip' flushes that try to run while a flush is already running. closes #2262