feat: enhance streamState handling in FormatConverter and RequestHandler

Author: bbbugg

src/core/FormatConverter.js

@@ -642,10 +642,9 @@ class FormatConverter {
                 id: streamId,
                 model: modelName,
                 object: "chat.completion.chunk",
-                usage: null,
             };
 
-            // Attach cached usage data to the very last message
+            // Attach cached usage data to the very last message (if available)
             if (streamState.usage) {
                 finalResponse.usage = streamState.usage;
             }

src/core/RequestHandler.js

@@ -418,7 +418,12 @@ class RequestHandler {
                         }
                         if (message.data) fullBody += message.data;
                     }
-                    const translatedChunk = this.formatConverter.translateGoogleToOpenAIStream(fullBody, model);
+                    const streamState = {};
+                    const translatedChunk = this.formatConverter.translateGoogleToOpenAIStream(
+                        fullBody,
+                        model,
+                        streamState
+                    );
                     if (translatedChunk) res.write(translatedChunk);
                     res.write("data: [DONE]\n\n");
                     this.logger.info("[Adapter] Fake mode: Complete content sent at once.");
@@ -838,7 +843,7 @@ class RequestHandler {
     }
 
     async _streamOpenAIResponse(messageQueue, res, model) {
-        const streamState = { inThought: false };
+        const streamState = {};
         let streaming = true;
 
         while (streaming) {