# A FlowSet based on a HashMap.
class FlowHashMap[K, V]
	super FlowSet
	super HashMap[K, V]

	# Init `self` with the content of `map`.
	init from(map: Map[K, V]) do
		init
		for k, v in map do self[k] = v
	end

	# Not a deep copy.
	redef fun clone do return new FlowHashMap[K, V].from(self)
end