FcgData create(Function f) {
		if (f == null) {
			return new EmptyFcgData();
		}

		FcgData data = cache.getUnchecked(f);
		return data;
	}
A factory that will create {@link FunctionCallGraph} data objects for a given function.  
Internally, this factory uses an MRU cache.
Ghidra/Features/GraphFunctionCalls/src/main/java/functioncalls/plugin/FcgDataFactory.java