Subscription does not work with extendType

[jasonkuhrt]

extendType does not support extending Subscription.

E.g. this does not work:

extendType({
  type: 'Subscription',
  definition(t) {
    t.boolean('truths', {
      subscribe() {
        return (async function* () {
          while (true) {
            await new Promise((res) => setTimeout(res, 1000))
            yield Math.random() > 0.5
          }
        })()
      },
      resolve(eventData) {
        return eventData
      },
    })
  },
})