@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + ((end == null) ? 0 : end.hashCode());
		result = prime * result + ((start == null) ? 0 : start.hashCode());
		return result;
	}
An edge between two functions.  This edge is never added to the graph, but exists for us
to maintain relationships between functions outside of the visual graph.
Ghidra/Features/GraphFunctionCalls/src/main/java/functioncalls/plugin/FunctionEdge.java