/guava/guava/src/com/google/common/util/concurrent/SequentialExecutor.java
workerRunningState ;
workerRunningState = RUNNING;
synchronized (queue) { if (!hasSetRunning) { if (workerRunningState == RUNNING) { return; } else { workerRunCount++; <extra_id_0> hasSetRunning = true; } } task = queue.poll(); if (task == null) { workerRunningState = IDLE;