Correct missing messages issue

[cpfiffer]

I was running into an error where the first streaming message that OpenAI sends is usually multiple messages lumped together, i.e.

data: {\"id\":\"chatcmpl-7lTNCpsoZCMd0oaDY1pe9gGunI7ZJ\",\"object\":\"chat.completion.chunk\",\"created\":1691548682,\"model\":\"gpt-3.5-turbo-0613\",\"choices\":[{\"index\":0,\"delta\":{\"role\":\"assistant\",\"content\":\"\"},\"finish_reas
on\":null}]}\n\ndata: {\"id\":\"chatcmpl-7lTNCpsoZCMd0oaDY1pe9gGunI7ZJ\",\"object\":\"chat.completion.chunk\",\"created\":1691548682,\"model\":\"gpt-3.5-turbo-0613\",\"choices\":[{\"index\":0,\"delta\":{\"content\":\"This\"},\"finish_reason\":null}]}\n\n

Note the data: entry about halfway through.

This PR is a convenience add for users who may not notice this -- all it does it separate out the "masterchunk" into sub-chunks split on newlines.

I also added some simpler checks for data: [DONE] messages.

[cpfiffer]

Tests seem due to a missing API key. How does this repo typically test API calls?

[roryl23]

There's a problem where running tests automatically from a fork doesn't work. I'm going to see if I can solve it right now. Currently we just run the tests manually before merge.

[roryl23]

I ran the tests locally, LGTM!