Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

Unlike with HTTP/2, the HTTP/3 implementation does not check for ReceivedEmptyRequestBody when creating the message body, which means the body detection feature returns true even for requests without one.

Expected Behavior

IHttpRequestBodyDetectionFeature returns false for requests where it's known from the start that there is no body.

Steps To Reproduce

• Send an HTTP/3 GET request to Kestrel
• Check IHttpRequestBodyDetectionFeature.CanHaveBody

Exceptions (if any)

N/A

.NET Version

No response

Anything else?

Hit in YARP when downgrading HTTP/3 requests to HTTP/1.1: dotnet/yarp#2644.