DistributedShardChangePublisher seems to be vulnerable to shard's data tree change events ordering

The scenario is as follows.

We have a DistributedShardChangePublisher that listens on shard's data tree change events and this shard has also some subshards. Then it seems that we are assuming that the DistributedShardChangePublisher will be notified with shard's data tree change event before any data tree change event from subshards.

Clearly we cannot assure that.