Close this store and release any resources.
Close this store and release any resources. It is undefined what happens if you merge after close
sets to .
sets to .plus(get(kv._1).get.getOrElse(monoid.zero), kv._2) but maybe more efficient implementations
merge a set of keys.
merge a set of keys.
The semigroup equivalent to the merge operation of this store
The semigroup equivalent to the merge operation of this store
Just get, locally merge, then put. This is only safe if there is only one writer thread per key. Otherwise you need to do some locking or compare-and-swap in the store