question: returns back pressure statistics for a operator . concode_field_sep StackTraceSampleCoordinator coordinator concode_elem_sep ExecutionJobVertex vertex concode_elem_sep int MAX_STACK_TRACE_DEPTH concode_elem_sep Logger LOG concode_elem_sep String EXPECTED_METHOD_NAME concode_elem_sep Cache<ExecutionJobVertex,OperatorBackPressureStats> operatorStatsCache concode_elem_sep Time delayBetweenSamples concode_elem_sep boolean shutDown concode_elem_sep Set<ExecutionJobVertex> pendingStats concode_elem_sep int numSamples concode_elem_sep int cleanUpInterval concode_elem_sep String EXPECTED_CLASS_NAME concode_elem_sep Object lock concode_field_sep long getCleanUpInterval concode_elem_sep OperatorBackPressureStats createStatsFromSample concode_elem_sep Void apply concode_elem_sep void cleanUpOperatorStatsCache concode_elem_sep void invalidateOperatorStatsCache concode_elem_sep boolean triggerStackTraceSample concode_elem_sep void shutDown
target: Option < OperatorBackPressureStats > function ( ExecutionJobVertex arg0 ) { return Option . apply ( operatorStatsCache . getIfPresent ( arg0 ) ) ; }