Missing Quic keep alive option to enable keep alive

[bentoi]

There's no option to enable keep alive on a Quic connection. As a consequence the Quic connection might idle timeout if there's no activity and even if an icerpc request is pending. This is quite bad IMO.

Should we consider adding a workaround to keep alive the Quic connection? One option would be to open an unidirectional stream to send a byte regularly (implemented in the Quic transport).

See also dotnet/runtime#87478. Hopefully this will motivate the Quic developers for adding this option.

[bernardnormier]

See also: microsoft/msquic#3880

[bentoi]

FYI, they added KeepAliveInterval which I believe can be used for this purpose: dotnet/runtime#94211

[bernardnormier]

Let's update the code conditionally (and add a test) once dotnet 9 preview 1 is out.