👨‍💼 We need to get rid of the toast value once we read it in the root.tsx. Here's how the API works:

session.set('key', 'value')
session.get('key') // 'value'

// then:
session.unset('key')

// then later:
session.get('key') // undefined

So we just want to add unset to .

But wait! We also need to make sure we commit the session. Any time you change the session, you need to make sure to let the client know otherwise it'll just keep sending you the old version of the cookie.