question: private UpstreamQueueState monitorUpstreamQueueAndPauseTraffic ( ) { if ( getUpstreamQueueStatus ( ) == UpstreamQueueState . FULL ) { if ( m_paused . compareAndSet ( false , true ) ) { pauseTraffic ( ) ; } return UpstreamQueueState . FULL ; } return UpstreamQueueState . EMPTY ; }
target:  - checks MessageService dispatch queue depth(highwatermark/ lowwatermark) and raise pause/resume to producer if needed