ATS QUIC project

[Masakazu Kitajo <ma...@apache.org>]

Hi,

This is a summary of a discussion about our QUIC project on the last ATS
summit.

Since every decision have to be made on ML with our community, I'm sending
this summary to make it official. Please reply to this thread if you have
any comments or questions.

# Target version
ATS 9.0 is the current target version. Since the QUIC specifications are
still not finalized it's technically out of our control, but we are going
to add QUIC support on 9.0 release if we can clear criteria below.

# Criteria
- QUIC module is buildable on every supported platforms -- but this doesn't
mean it comes with good performance on every platforms due to lack of
better UDP socket support
- QUIC module works with pure OpenSSL -- currently it requires a modified
OpenSSL but we will wait for an official release that supports APIs
required for QUIC implementation
- HTTP/QUIC is available -- since nobody is interested in early access for
QUIC *transport layer*

# Merging
- Before 9.0 branching --  it should not be at the last minute
- With one commit -- depends on another discussion about merging policy but
there's no reasons to keep older commits on quic-latest branch

# Others
- We only support IETF QUIC but not Google QUIC

Thanks,
Masakazu