/guava/android/guava/src/com/google/common/util/concurrent/SequentialExecutor.java
checkNotNull ( task ) ; Runnable submittedTask;
@RetainedWith private final QueueWorker worker = new QueueWorker(); SequentialExecutor(Executor executor) { this.executor = Preconditions.checkNotNull(executor); } @Override public void execute(Runnable task) { <extra_id_0> long oldRunCount; synchronized (queue) { if (workerRunningState == RUNNING || workerRunningState == QUEUED) { queue.add(task); return; }