Any idea why there would be a test failure here after refactoring `-insetWidth:height:nullRect:` to use `-insetBy:nullRect:`? 

Logging `result` shows these values:

```
{{13, 15}, {14, 10}}
{{13, 15}, {14, 10}}
{{13, 25}, {24, 30}}
{{13, 25}, {24, 30}}
{{28, 20}, {39, 25}}
```
Some of them are being sent twice. Is there something wrong with the way I refactored those methods?