Small improvement to `apply`
Small improvement to `apply`

Copying structs around is not ideal, so let's take the dangerous
approach of making sure we only mutate the right ones, forever!

zackmdavis/Leafline,FoxLisk/Leafline,FoxLisk/Leafline,zackmdavis/Leafline,zackmdavis/Leafline,zackmdavis/Leafline,FoxLisk/Leafline,FoxLisk/Leafline