Method getSizeUsed

fdbserver/VersionedBTree.actor.cpp:1947–1947

		int64_t getCountUsed() const { return evictionOrder.size() + movedOutCount; }
		int64_t getCountMoved() const { return movedOutCount; }
		int64_t getSizeUsed() const { return sizeUsed + reservedSize; }

		// Only to be used in tests at a point where all ObjectCache instances should be destroyed.
		bool empty() const { return reservedSize == 0 && sizeUsed == 0 && getCountUsed() == 0; }