• [API] Add per-connection send rate throttling.
• [BUGFIX] Fix data corruption in delayed mini-conn packets (#593).
• [BUGFIX] Allow split buffered packet to generate one packet. (This
  can happen when DPLPMTUD increases a path's MTU.) (#505).
• [BUGFIX] HTTP/3 client GOAWAY frame generation (#343).
• [TUNING] QUIC Interop: add zerortt support.
• Improve logs in the Extensible HTTP/3 Priority (HPI) module.
• Comment cleanup: update QUIC draft references to RFC references.
• Teach http_client to send "priority" header.
• Parallelize unit tests so that they finish faster.
• Include QUIC Interop Runner docker files in the distribution.