public void update(TransactionBase tx, Map<K, V> updates) {
    combineQ.addAll(tx, updates);
  }
public void update ( TransactionBase tx , Map < K , V > updates ) { combineQ . addAll ( tx , updates ) ; }
Queues updates for a collision free map. These updates will be made by an Observer executing
another transaction. This method will not collide with other transaction queuing updates for
the same keys.

@param tx This transaction will be used to make the updates.
@param updates The keys in the map should correspond to keys in the collision free map being
updated. The values in the map will be queued for updating.