UseMiddleware doesn't work as expected with subscriptions

[rigelglen]

Describe the bug
I have a custom checker middleware that I'm using on regular queries with @UseMiddleware(CustomMiddleware), when I try to use that on a subscription, the middleware is not called when the subscription is first queried (which is when authorization checks should happen). The middleware is called when the resolver receives a pubsub message.

However, if I use @Authorized(), the auth checker middleware gets called when you first query the subscription.

To Reproduce

@UseMiddleware(CustomMiddlware)
@Subscription(
topics: 'SOME_TOPIC'
)
async mySubscription()

// Middleware will only get called when a new message comes in.

Expected behavior
Middleware should get called when first subscribing to the subscription (onConnect)

Environment (please complete the following information):

• OS: any
• Node 13.12.0
• Package version: 0.18.0-beta.10 (also tested on 0.17.6)
• TypeScript version 3.8.3

Additional context

I've set up a minimal test repo here https://github.com/rigelglen/typegraphql-middleware-subscription-test

You can reproduce using the following

subscription{
  normalSubscriptionWithMiddleware{
    id
    message
    date
  }
}

And then

mutation {
  pubSubMutation(message: "something")
}

[MichalLytek]

Duplicate of #200 🔒

For now only @Authorized is supported during subscribe phase.
However, as a workaround you can provide custom subscribe function that will contain the auth logic.