Stream the tool calling rounds of every Chat Completions provider

app/MindWork AI Studio/Provider/OpenAI/ChatCompletionToolCallDelta.cs

@@ -0,0 +1,15 @@
+namespace AIStudio.Provider.OpenAI;
+
+/// <summary>
+/// One fragment of a tool call in a streamed Chat Completions answer.
+/// </summary>
+/// <remarks>
+/// A tool call arrives in pieces: the ID and the name usually with the first fragment, the
+/// arguments spread over as many as the model needs. The index is what ties the pieces of one
+/// call together while another call is being written at the same time.
+/// </remarks>
+/// <param name="Index">Which call this fragment belongs to; null when the provider omits it.</param>
+/// <param name="Id">The ID of the call, sent once by most providers and repeated by some.</param>
+/// <param name="Type">The kind of call, which is "function" for everything we offer.</param>
+/// <param name="Function">The name and the arguments fragment of the call.</param>
+public sealed record ChatCompletionToolCallDelta(int? Index, string? Id, string? Type, ChatCompletionToolFunction? Function);