No need for another class either, please just add a property like "disableGC" or something better, and [above](https://github.com/erikvold/addon-sdk/blob/86389ae45c51b4e194c048c0a51e98e658fe5ab1/lib/sdk/core/disposable.js#L32) use strong reference if `instance.disableGC` is `true`. I'm sure you can come up with a better name for this property.