private long queueLock(LockRequest lockRequest) throws ServiceException {
    LockResponse response = masterRpcService.requestLock(null, lockRequest);
    return response.getProcId();
  }
Returns immediately if the lock is acquired.
@throws TimeoutException if lock couldn't be acquired.
hbase-server/src/test/java/org/apache/hadoop/hbase/master/locking/TestLockProcedure.java