code: public void setSomePendingWritesAndSave(
        final long atTime,
        final BsonDocument atVersion,
        final long atHash,
        final ChangeEvent<BsonDocument> changeEvent
    ) {
      docLock.writeLock().lock();
      try {
        this.setSomePendingWrites(atTime, atVersion, atHash, changeEvent);
        docsColl.replaceOne(
            getDocFilter(namespace, documentId),
            this);
      } finally {
        docLock.writeLock().unlock();
      }
    }
docs: Sets that there are some pending writes that occurred at a time for an associated
  locally emitted change event. This variant updates the last version set.
  
  @param atTime      the time at which the write occurred.
  @param atVersion   the version for which the write occurred.
  @param changeEvent the description of the write/change.