Make transport parameters varint

[DavidSchinazi]

Now that transport parameters are represented using QUIC encoding (as opposed to TLS presentation language), the remaining 16-bit fields stick out like sore thumbs. This PR makes transport parameters consistent with the rest of the document.

Fixed #3294.

[martinthomson]

I thought that we had consensus to leave these alone.

I do have one comment in the spirit of the PR though.

[martinthomson]

@DavidSchinazi, as we have decided not to do this, can we close this? (It doesn't have an issue, so if we wanted to pursue it, we'd need one.)

[DavidSchinazi]

@martinthomson I don't think we've quite decided not to do this yet. The sense I got in the room in Cupertino was that some folks were opposed to changing this, but the main opposition was the fact that I had conflated three issues into one (TLS presentation language, IANA registry, varint). The first one #3108 was merged, the second one #3170 is almost merged. I was thinking of filing a new issue and rebasing this PR when #3170 gets merged to have a conversation specific to this change.

[dtikhonov]

My recollection matches that of @martinthomson. Unfortunately, I don't see it in the IETF 106 minutes and I don't have it in my own notes (I wasn't documenting every issue we covered...)

[kazuho]

FWIW my recollection also matches that of @martinthomson, and the relevant minutes are at https://github.com/quicwg/wg-materials/blob/master/interim-19-10/minutes.md#issue-3020-transport-parameter-registry-changes. It was discussed in Cupertino.

[marten-seemann]

I agree with @DavidSchinazi. Now that we're not using TLS presentation language any more, there's no need to continue using uint16s.

[kazuho]

I agree with @DavidSchinazi. Now that we're not using TLS presentation language any more, there's no need to continue using uint16s.

I disagree with that way of thinking, as it is my understanding that we agreed on moving away from TLS presentation language based on the premise that we would be using 16-bit lengths.

[ianswett]

The notes are really sparse on the varint conversation, varint is mentioned 3 times.

Because this issue was conflated with other issues, it wasn't discussed much by itself. I thought we decided to split it up, do the first two, and then discuss the third, which I remember some in the room commenting wasn't going to happen, but I didn't think that constituted consensus of any sort.

All that said, unless we have strong support for changing this, I think the status quo wins.

[DavidSchinazi]

I've now created issue #3294 so we can move the conversation there.

[martinthomson]

Thanks for doing this David. I can't see any problem with this, but we have to wait the full consensus call cycle before it lands.