[BUG] A2A协议流式传输存在两个严重bug，1.1.2.0版本。 #4285
Description
Is there an existing issue for this?
- I have searched the existing issues
Current Behavior
- 虚假流式传送，client agent是流式输出，但是server agent是一次性返回的
- 返回的内容存在重复，跟studio中的bug相同，流式响应式答案输出了两次
Expected Behavior
No response
Steps To Reproduce
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Environment
Spring AI Alibaba version(s):Debug logs
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Anything else?
No response