fix: make last stream message to send empty content

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

api/openai/chat.go

@@ -18,8 +18,9 @@ import (
 )
 
 func ChatEndpoint(cm *config.ConfigLoader, o *options.Option) func(c *fiber.Ctx) error {
+	emptyMessage := ""
+
 	process := func(s string, req *OpenAIRequest, config *config.Config, loader *model.ModelLoader, responses chan OpenAIResponse) {
-		emptyMessage := ""
 		initialMessage := OpenAIResponse{
 			Model:   req.Model, // we have to return what the user sent here, due to OpenAI spec.
 			Choices: []Choice{{Delta: &Message{Role: "assistant", Content: &emptyMessage}}},
@@ -222,7 +223,7 @@ func ChatEndpoint(cm *config.ConfigLoader, o *options.Option) func(c *fiber.Ctx)
 						{
 							FinishReason: "stop",
 							Index:        0,
-							Delta:        &Message{},
+							Delta:        &Message{Content: &emptyMessage},
 						}},
 					Object: "chat.completion.chunk",
 				}