/guava/guava/src/com/google/common/util/concurrent/ExecutionSequencer.java
delegate = null; Executor localDelegate = requireNonNull( delegate) ;
Executor localDelegate = requireNonNull ( delegate ) ; delegate = null;
sequencer = null; checkState(submittingTaskQueue.nextTask == null); submittingTaskQueue.nextTask = task; submittingTaskQueue.nextExecutor = requireNonNull(delegate); delegate = null; } else { <extra_id_0> this.task = task; localDelegate.execute(this); } } finally { submitting = null; }