2.2.1

Changed

• Retry tokens are accepted for at most 10 seconds, so a captured token
  can no longer be replayed later.

Fixed

• A large download could be closed with a flow-control error, seen as a
  transfer that stopped part way. The sender counted its connection credit
  in bytes sent while the receiver counts the highest offset on each
  stream, as the RFC says, so a write that went out ahead of data still
  queued made the two disagree. The sender now counts the same way.
• quic:migrate/1 on a server connection closed the listener's socket,
  breaking every connection on it. It now returns
  {error, not_supported_on_server}.
• A resumed connection could send more 0-RTT data than the server's
  current limits allowed, and a server with lower limits closed the
  connection. A ticket now keeps the server's limits and 0-RTT data stays
  within them; what does not fit waits for the handshake to finish. A
  ticket stored by an older version is used without 0-RTT.
• A server whose client moves to a new address sends it at most three
  times what it received from there until the address is validated, goes
  back to the old address when validation fails, and follows only the
  newest packet, so a late or spoofed packet no longer moves it. An
  answer to any of its earlier checks of the address counts, a slow new
  path gets time to answer, and the path must carry full-size packets
  before it is validated. The same holds for a client that moves during
  the handshake.
• After a client moves, the server uses a new connection ID towards the
  new address unless the client kept its own, from the first packet it
  sends there.
• Packets sent before a migration no longer feed the new path's RTT
  estimate or congestion window, and PMTU is searched again on the new
  path. A client's own migration resets its congestion state once the new
  path is validated.
• A connection that moves to a new path keeps the congestion control it was
  configured with. Each path change started over with NewReno and the default
  windows, whatever cc_algorithm, initial_window and minimum_window
  said, and quic:set_congestion_control/2 also dropped those windows.