Stream issues in FastAPI web app hosted on IIS with HttpPlatformHandler v2 RC3

[NewGHUser4321]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

FastAPI app is hosted on IIS with HttpPlatformHandler as in this blog. Works fine for normal response. When the response is streamed, instead of getting chunks as is from the server, I'm getting bunch of chunks at a time on client side. After some research, I saw this blog where it mentions SSE(Server-Sent Events) issues with HttpPlatformHandler v1.2 (from Microsoft). I upgraded it to HttpPlatformHandler v2 RC3, still no luck. It seems to be doing the same. Please note that streaming works fine when I run the Uvicorn server manually and access the streaming endpoint. Isse is only when I access the IIS hosted endpoint.

Expected Behavior

Stream chunks of data as is without caching.

Steps To Reproduce

Streaming data exactly as in this repo
Look at the /stream endpoint

Exceptions (if any)

No response

HttpPlatformHandler Version

HttpPlatformHandler v2 RC3

Anything else?

No response