private void createThunkFunctionCallGraph() throws Exception {

		/*
		 	
			node1
			0010 -> Function @ 0100
			
				node2
				Call: 0100 -> Thunk_Function_1050 @ 1050
				
					node3
					Call: 1050 -> Function_1100 @ 1100
					
						node4
						Call: 1100 -> 1200
		 */

		String thunkedAddress = "0x1100";
		Function thunkedFunction =
			builder.createEmptyFunction("Function_1100", thunkedAddress, 10, DataType.DEFAULT);
		builder.createMemoryCallReference("0x1100", "0x1200"); // ref so a node appears in the tree

		String thunkAddress = "0x1050";
		Function thunkFunction =
			builder.createEmptyFunction("Thunk_Function_1050", thunkAddress, 10, DataType.DEFAULT);
		tx(() -> {
			thunkFunction.setThunkedFunction(thunkedFunction);
		});

		builder.createMemoryCallReference(firstCalledFunctionAddress, thunkAddress);
		builder.createMemoryCallReference(thunkAddress, thunkedAddress);
	}
This test class is covering the various types of 'calls' a function can make, such as a
direct call instruction, or through a user-defined reference.   External calls are also a bit
tricky.   This test was created by following the code paths in {@link OutgoingCallNode}
and making sure that each path was followed.
Ghidra/Features/Base/src/test.slow/java/ghidra/app/plugin/core/calltree/OutgoingCallNodeTest.java