Reproduction of

Steps:

1. First, npm install
2. Run npm run production
3. Open http://localhost:5000
4. Take a heap snapshot and look for a Map related to watchDep prop of InMemoryCache
5. Click Unmount button
6. Take a heap snapshot again and look for a Map related to watchDep prop of InMemoryCache
7. There's still a record for the query, with callback