Syntax:
pragma Favor_Top_Level (type_NAME);
The argument of pragma Favor_Top_Level must be a named access-to-subprogram
type. This pragma is an efficiency hint to the compiler, regarding the use of
'Access or 'Unrestricted_Access on nested (non-library-level) subprograms.
The pragma means that nested subprograms are not used with this type, or are
rare, so that the generated code should be efficient in the top-level case.
When this pragma is used, dynamically generated trampolines may be used on some
targets for nested subprograms. See restriction No_Implicit_Dynamic_Code.