Share and modify variables between Express and the GraphQL/Apollo server
**Background on my application**

I have an Express application with the `apollo-server-express` package installed, which allows me to attach a GraphQL server to the running Express server.

The Express server is used for authentication/authorization (with Keycloak and Passport), and the GraphQL server serves as the API layer for querying data.

**What I'd like to accomplish**

Implement a way to auto logout users when they have been inactive for 10 minutes. "Inactive" is defined as users from making a query to the GraphQL server.

**My current strategy**

Create a global variable when initializing the Express application that tracks each logged-in user and the last time that they made a request. Example:
```
const userSessionTracker = {
    userId1: 300000, // a user's timer: last time they logged in/made a request (in ms)
    userId2: 5000,
    ...
}
```
Every time a user logs in/makes a request, the application will reset their timer back to 0. Next time they make a request, if the timer is above 10 minutes, the application will log the user out.

**Problem**

When the users call a GraphQL query, I'd like to check/reset their timer inside the GraphQL query resolver. How can I do so?

**What I've tried**

- Passed `userSessionTracker` into the Apollo server's `context`, enabling the variable to be accessible from the resolver's `contextValue`
- Tried editing `userSessionTracker` from inside the resolver
- `console.log(userSessionTracker)` from the Express server
- Expected `userSessionTracker` to show the edits made from the GraphQL resolver, but saw that it remains in the state it was in before the edits were made

In summary, I can access the `userSessionTracker` variable from inside a GraphQL resolver, but I can't edit it and have the edited version be accessible from the Express application.

This seems to be by design, as the Apollo docs stated that "Resolvers should never destructively modify the contextValue argument". How can I get around this limitation?