Threads endpoint remapping

[BoHomola]

Implemented and mapped most of the endpoints for Threads (thread, messages, run, run steps)

https://platform.openai.com/docs/api-reference/threads
https://platform.openai.com/docs/api-reference/messages
https://platform.openai.com/docs/api-reference/runs
https://platform.openai.com/docs/api-reference/run-steps

Still missing: Submit tool outputs to run, more complex demo cases (currently only file info extraction is showcased).

[lofcz]

this will be resolved in a follow-up pr? See ChatRequest for a reference - we give users both fields to use, if the implementing IEnumerable<> one is filled it has precedence when serializing the request.

[BoHomola]

Since this is a request and won't be de-serialized, I left only the array (since it support text content as well) and if a message with a single string content needs to be created, for the simplicity I overloaded a constructor, that automatically constructs the array with text content. What do you think?

[lofcz]

added a few ctor overloads in 3c79c73, which should solve this

[lofcz]

memento to check this out

[lofcz]

Tried running all the threads tests:

• DeleteMessage, DeleteRun failed with 404 / 405, though they work fine when run standalone
• ListRunSteps, RetrieveRunStep failed on JSON deserialization (again, they work fine when run standalone)

Test failed with exception: Cannot deserialize the current JSON array (e.g. [1,2,3]) into type 'LlmTornado.Threads.ToolCalls' because the type requires a JSON object (e.g. {"name":"value"}) to deserialize correctly.

Some nits:

• CreateThreadAndRunRequest should accept ChatModel (we might specialize into AssistantModel later, possibly generating the code), there are also some nullability issues in the file.
• SubmitToolOutputsRequest has some nullability issues.
• In ThreadsEndpoint RestDataOrException<HttpResponseMessage> was sometimes not propagated correctly, fixed in f202c34
• FileSearchTool seems finished by OpenAI? So instead of object, ToolFileSearchConfig should be used? (in public sealed class FileSearchToolCall : ToolCall).
• In ToolFileSearchConfig shouldn't it be max_num_results instead of max_num_result? (https://platform.openai.com/docs/api-reference/runs/createRun)
• RankingOptions.Ranker should be en enum with auto, default_2024_08_21 (https://platform.openai.com/docs/assistants/tools/file-search#customizing-file-search-settings).
• There are still some System.Text.Json.Serialization usings, we should get rid of them.
• RequiredAction.Type should be an enum.

Overall, this looks really good and consistent! Looking forward to more tests, streaming, and wrapping this up. Let me know when this is ready.

[lofcz]

Pushed a few changes, and optimized Assistants streaming. To wrap this up:

• Please add missing XML docs, currently many public APIs introduced are undocumented.
• When possible, prefer FrozenDictionary lookup over patterns like ToolChoiceType? toolType = JsonConvert.DeserializeObject<ToolChoiceType>($"\"{reader.Value}\""); (see changes to ThreadsEndpoint in 27a4d77 for a reference) - this reduces allocations & increases throughput significantly, given we incur the penalty on each event received.
• Add tests invoking code_interpreter, file_search to increase coverage.

[lofcz]

Thanks for working on this!