rb_enumerator_size_func  121 enumerator.c       rb_enumerator_size_func *size_fn;
rb_enumerator_size_func  228 include/ruby/intern.h VALUE rb_enumeratorize_with_size(VALUE, VALUE, int, const VALUE *, rb_enumerator_size_func *);
rb_enumerator_size_func  231 include/ruby/intern.h     rb_enumeratorize_with_size(obj, id, argc, argv, (rb_enumerator_size_func *)(size_fn))