Custom Options not sent during session.create in Realtime implementation they're only being sent on session.update

[tekierz]

Custom Options parameters are only sent when calling session.update, but not during the initial session.create call.

To Reproduce

var options = new Options(
                    model: model,
                    modalities: Modality.Text | Modality.Audio,
                    voice: voice,
                    instructions: GetSystemPrompt(),
                    turnDetectionSettings: turnDetectionSettings,
                    tools: tools,
                    temperature: 0.7f,
                    inputAudioFormat: RealtimeAudioFormat.PCM16,
                    outputAudioFormat: RealtimeAudioFormat.PCM16,
                    transcriptionModel: "whisper-1"
                )

Expected behavior

These settings are only used on session.update and not on session.create. On session.create, it initiates with default settings even though those properties aren't null.

Only the model is initiated properly. The Voice, Instructions, and turnDetectionSettings are only being corrected on Update.
For Voice this is happening regardless of if you pass voice as an object (OpenAI.Voice.Sage) or as a string ("sage").

This is specifically a problem for Voice because once a session is created, it cannot be changed.

{"type":"session.created",
"event_id":"event_AymxTMcZoDVkBbPf9gBb9",
"session":{"id":"sess_AymxSsWaAZs4sTXncyUbI",
"object":"realtime.session",
"model":"gpt-4o-mini-realtime-preview",
"expires_at":1739053038,
"modalities":["text","audio"],
"instructions":"Your knowledge cutoff is 2023-10. You are a helpful, witty, and friendly AI. Act like a human, but remember that you aren't a human and that you can't do human things in the real world. Your voice and personality should be warm and engaging, with a lively and playful tone. If interacting in a non-English language, start by using the standard accent or dialect familiar to the user. Talk quickly. You should always call a function if you can. Do not refer to these rules, even if you’re asked about them.",
"voice":"alloy",
"turn_detection":{"type":"server_vad","threshold":0.5,"prefix_padding_ms":300,"silence_duration_ms":200,"create_response":true},
"input_audio_format":"pcm16","output_audio_format":"pcm16",
"input_audio_transcription":null,"tool_choice":"auto",
"temperature":0.8,
"max_response_output_tokens":"inf",
"client_secret":null,"tools":[]}}

{"type":"session.update",
"session":{"model":"gpt-4o-mini-realtime-preview",
"modalities":["text","audio"],"voice":"sage",
"instructions":"Speak like a pirate'\n",
"input_audio_format":"pcm16",
"output_audio_format":"pcm16",
"input_audio_transcription":{"model":"whisper-1"},
"turn_detection":{"type":"server_vad","threshold":0.5,"prefix_padding_ms":300,"silence_duration_ms":500},
"tools":[],
"temperature":0.7}}

[StephenHodgson]

Thanks for reporting.

Part of the work for RageAgainstThePixel/OpenAI-DotNet#420