Passing request parameter into middleware using createHandler function of graphql-http

I have created an express server which uses GraphQL for handling requests over HTTP. Among others, the express server has the two middlewares below.

app.use(authenticate);

app.use('/graphql', createHandler({ schema }));

The authenticate middleware invokes a function which has req, res and next as parameters and in certain conditions assigns a value to req.user.

How can I pass the req object into the next middleware which is responsible for handling GraphQL requests?

I’ve searched for it in graphql-http’s documentation but no luck. Any help will be appreciated.
Link to the package’s documentation: https://github.com/graphql/graphql-http#with-express