Feat: sse_streaming

[jayy-77]

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#4240

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[gemini-code-assist]

Summary of Changes

Hello @jayy-77, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a significant feature that enables Server-Sent Events (SSE) streaming for agents when they are converted into A2A Starlette applications. This enhancement provides a mechanism for real-time, incremental delivery of agent responses, improving user experience by allowing data to be pushed from the server to the client as it becomes available. The changes involve adding a new configuration option for streaming and integrating it across various components of the ADK framework to support this functionality.

Highlights

• SSE Streaming Support: Introduced the StreamingMode enum to enable Server-Sent Events (SSE) for real-time streaming of agent responses, enhancing the responsiveness of agent applications.
• Configurable Streaming Mode: The to_a2a utility function now accepts an optional streaming_mode parameter, allowing users to explicitly configure the desired streaming behavior, such as StreamingMode.SSE.
• Internal Integration: The chosen streaming_mode is seamlessly propagated through the A2aAgentExecutorConfig and request_converter components, ensuring that the agent's RunConfig respects the specified streaming preference during execution.

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[adk-bot]

Response from ADK Triaging Agent

Hello @jayy-77, thank you for your contribution!

To help us review this PR, could you please fill out the "Testing Plan" section in the PR description? This information is important for the reviewers to understand how you have tested your changes.

You can find more details in our contribution guidelines.

Thanks!

[gemini-code-assist]

Code Review

This pull request introduces Server-Sent Events (SSE) streaming capabilities by integrating a StreamingMode enum throughout the A2A conversion and execution pipeline. The changes correctly propagate the streaming_mode from the to_a2a function, through the A2aAgentExecutorConfig, and into the RunConfig used by the ADK runner. The implementation ensures that if no specific streaming mode is provided, it defaults to StreamingMode.NONE, maintaining existing behavior. The code is well-structured, and the docstrings and type hints have been updated appropriately to reflect the new parameter, enhancing clarity and maintainability.