code: private Task<Void> release() {
      return PlanLocal.get(getPlanLocalKey(), LockInternal.class).flatMap(lockInternal -> {
        // should never be null.
        if (lockInternal == null) {
          LOG.error("LockInternal is null when releasing lock: ", _lockPath);
        } else {
          lockInternal._lockCount--;
          if (lockInternal._lockCount == 0) {
  
            return PlanLocal.remove(getPlanLocalKey())
                .flatMap(unused ->
                    _zkClient.delete(lockInternal._lockNode, -1)
                        .recover(e -> {
                          _zkClient.deleteNode(lockInternal._lockNode);
                          return null;
                        })
                );
          }
        }
        return Task.value(null);
      });
    }
docs: Try to release the lock.