I somehow got around the Unknown directive part. I checked realtime.ts again and restarted server.
Now graphql returns somthing that looks good, but it seems Apollo does not read it correctly.
Error: JSON.parse: unexpected non-digit at line 2 column 2 of the JSON data
Response
--- // i think apollo refers to this line 2 column 2?!
Content-Type: application/json; charset=utf-8
Content-Length: 65
{"data":{"fastField":"I am fast"},"hasNext":true,"extensions":{}}
---
Content-Type: application/json; charset=utf-8
Content-Length: 115
{"incremental":[{"data":{"__typename":"Query","slowField":"I am slow"},"path":[]}],"hasNext":false,"extensions":{}}
-----
This somehow has to do with apollo not being ale to use multipart?