feat: support stream_options (#736)

* feat: support stream_options

* fix lint

* fix lint

chat.go

@@ -216,6 +216,16 @@ type ChatCompletionRequest struct {
 	Tools        []Tool `json:"tools,omitempty"`
 	// This can be either a string or an ToolChoice object.
 	ToolChoice any `json:"tool_choice,omitempty"`
+	// Options for streaming response. Only set this when you set stream: true.
+	StreamOptions *StreamOptions `json:"stream_options,omitempty"`
+}
+
+type StreamOptions struct {
+	// If set, an additional chunk will be streamed before the data: [DONE] message.
+	// The usage field on this chunk shows the token usage statistics for the entire request,
+	// and the choices field will always be an empty array.
+	// All other chunks will also include a usage field, but with a null value.
+	IncludeUsage bool `json:"include_usage,omitempty"`
 }
 
 type ToolType string