add note about empty function objects (#19)

* document what to do for empty function objects

* add link to more complete description

* link to a specific comment, rather than the issue

content/getting_started/Examples.md

@@ -250,6 +250,10 @@ printf("dfdy = %f\n", dfdy);
 // prints dfdy = 5.500000
 ```
 
+> Note: if the member function belongs to a class or struct with no member variables,
+it may be optimized away at the call site, which disrupts the argument ordering and
+leads to an error. See: https://github.com/EnzymeAD/Enzyme/issues/1388#issuecomment-1728114457 for more information on a workaround.
+
 A more general implementation of the wrapper function (that works with
 different objects and argument types) is given below: