$ perl -MDevel::Size=total_size -E'$key=123;$foo{$key}=1;$foo[$key]=1;say total_size\%foo;say total_size\@foo'
205
1080
$ perl -MDevel::Size=total_size -E'$key=123456;$foo{$key}=1;$foo[$key]=1;say total_size\%foo;say total_size\@foo'
208
987744
$ perl -MDevel::Size=total_size -E'$key=123456789;$foo{$key}=1;$foo[$key]=1;say total_size\%foo;say total_size\@foo'
211
987654408