Stream order issue in nested agent via tool call

execute: async ({ context, runtimeContext }) => {
        const messageId = runtimeContext.get("messageId") as NewChatRuntimeContext["messageId"];
        const stream = await SandboxAgent.stream(
            [
                {
                    id: messageId,
                    role: "assistant",
                    content: [
                        context.task ? `Task: ${context.task}` : undefined,
                        context.goal ? `Goal: ${context.goal}` : undefined,
                    ]
                        .filter(Boolean)
                        .join("\n") || "Execute the assigned task.",
                },
            ],
            {
                format: "aisdk",
                runtimeContext: runtimeContext,
                stopWhen: stepCountIs(context.maxSteps),
                memory: {
                    thread: threadId,
                    resource: userId,
                },
            },
        );
        // Stream sub-agent UI events to the runtime UI writer in real-time
        writer.merge(
            stream.toUIMessageStream({
                sendReasoning: true,
                sendStart: false,
                sendFinish: false,
                generateMessageId: () => messageId,

            }),
        );

        // Stream the sub-agent output through this tool’s stream
        // await stream.fullStream.pipeTo(mastraWriter!);

        // Drive the stream consumption so events flow
        stream.consumeStream();

        return {
            message: `Transferred to sandbox agent`,
        };
    },