const streamContext = getStreamContext();

    if (streamContext) {
      return new Response(
        await streamContext.resumableStream(streamId, () =>
          stream
            .toUIMessageStream({
              newMessageId: crypto.randomUUID(),
              onFinish: async ({ responseMessage }) => {
                await saveMessages({
                  messages: [
                    {
                      ...responseMessage,
                      createdAt: new Date().toISOString(),
                      updatedAt: new Date().toISOString(),
                      attachments: [],
                      chatId: id,
                    } as DBMessage,
                  ],
                });
              },
              sendStart: true,
              sendFinish: true,
              sendReasoning: true,
              sendSources: true,
            })
            .pipeThrough(
              new TransformStream({
                transform(chunk, controller) {
                  if (chunk.type === "text") {
                    controller.enqueue(chunk.text);
                  }
                },
              }),
            ),
        ),
      );
    }

    return createUIMessageStreamResponse({
      stream: stream.toUIMessageStream({
        sendFinish: true,
        sendReasoning: true,
        sendSources: true,
        sendStart: true,
        newMessageId: crypto.randomUUID(),
        onFinish: async ({ responseMessage }) => {
          await saveMessages({
            messages: [
              {
                ...responseMessage,
                createdAt: new Date().toISOString(),
                updatedAt: new Date().toISOString(),
                attachments: [],
                chatId: id,
              } as DBMessage,
            ],
          });
        },
      }),
    });

  const {
    messages,
  } = useChat({
    onFinish: async (opts) => {
       console.log(opts)
    },
    ...
  });