title: how to stream data from cloud functions to cloud storage
body: <p>I'm trying to create a cloud function which saves some data (documents from firestore) to cloud storage.</p>
  
  <p>Wrote some cloud functions before, but kind of new to cloud storage, buckets etc.
  From what I've read I have to "stream" this data to a bucket.</p>
  
  <p>I'd love to see a short snippet that does just that :)</p>