C# Bug: Trying new ChatGPT API on gpt-3.5-turbo model (bug in developer code)

Amending here: although I get Success, the first line that I am reading is this:

data: {“id”:“chatcmpl-6psQJ649lGZpci17HgPLAR3tDkYxS”,“object”:“chat.completion.chunk”,“created”:1677821951,“model”:“gpt-3.5-turbo-0301”,“choices”:[{“delta”:{“role”:“assistant”},“index”:0,“finish_reason”:null}]}

no resemblance to the documentation:

{
  "id": "chatcmpl-123",
  "object": "chat.completion",
  "created": 1677652288,
  "choices": [{
    "index": 0,
    "message": {
      "role": "assistant",
      "content": "\n\nHello there, how may I assist you today?",
    },
    "finish_reason": "stop"
  }],
  "usage": {
    "prompt_tokens": 9,
    "completion_tokens": 12,
    "total_tokens": 21
  }
}