[SOLVED] Using `client.subscribe` does not work? (to AppSync, from Node)

Client SDKs
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4

Update: I I have described in Using Apollo with AppSync directly on iOS - #3 by holyjak, I am getting the same error as the author there:

ws.msg {"type":"connection_ack","payload":{"connectionTimeoutMs":300000}}
ws.msg {"type":"ka"}
ws.msg {"type":"error","payload":{"errors":[{"errorType":"UnsupportedOperation","message":"unknown not supported through the realtime channel"}]}}

The problem is also discussed in this AWS forum /message.jspa?messageID=935705 with some valuable reference, with this conclusion:

To get AppSync Subscriptions working with subscription-transport-ws, you need to follow the instructions in this GitHub issue: Document how to use client with AppSync · Issue #224 · apollographql/apollo-feature-requests · GitHub