Of_storage.Mtype key = Key.ttype value = Value.tfind t k is Some v if k is associated to v in t and None is k is not present in t.
batch t f applies the operations in f in a batch. The exact guarantees depend on the implementation.
val clear : t -> unitclear t clears the storage. This operation is expected to be slow.
val close : t -> unitclose t frees up all the resources associated with t.