`IHttpRequestBodyDetectionFeature` returns true for GET requests with HTTP/3

[MihaZupan]

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.

aspnetcore/src/Servers/Kestrel/Core/src/Internal/Http2/Http2Stream.cs

Lines 194 to 211 in 46ea84f

	protected override MessageBody CreateMessageBody()
	{
	if (ReceivedEmptyRequestBody)
	{
	return MessageBody.ZeroContentLengthClose;
	}
	if (_messageBody != null)
	{
	_messageBody.Reset();
	}
	else
	{
	_messageBody = new Http2MessageBody(this);
	}
	return _messageBody;
	}

aspnetcore/src/Servers/Kestrel/Core/src/Internal/Http3/Http3Stream.cs

Lines 947 to 959 in 46ea84f

	protected override MessageBody CreateMessageBody()
	{
	if (_messageBody != null)
	{
	_messageBody.Reset();
	}
	else
	{
	_messageBody = new Http3MessageBody(this);
	}
	return _messageBody;
	}

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.