public boolean unlock() {
    if (subscriptionInfoHolder != null) {
      subscriptionInfoHolder.set(null);
      subscriptionInfoHolder = null;
    }

    try {
      coordinatorLock.unlock();
      return true;
    } catch (IllegalMonitorStateException ignored) {
      // This is thrown if unlock() is called without lock() called first.
      LOGGER.warn("This thread is not holding the lock.");
      return false;
    }
  }
Lock the {@link SubscriptionInfo} coordinator.

@return the {@link SubscriptionInfo} holder, which can be used to get the {@link
    SubscriptionInfo}. Wait until lock is acquired
iotdb-core/confignode/src/main/java/org/apache/iotdb/confignode/manager/subscription/SubscriptionCoordinator.java