Breaking Changes:

• Connection::set_discover_pmtu_in_handshake() now takes a max_probes argument.
• The C API congestion control enum now exposes QUICHE_CC_BBR2_GCONGESTION instead of QUICHE_CC_BBR and QUICHE_CC_BBR2. The bbr and bbr2 string aliases still select the gcongestion BBR2 implementation.
• StartupExitReason gained a ConservativeSlowStartRounds variant, so exhaustive matches need to be updated.

Highlights:

• Added Config::set_pmtud_max_probes() so DPLPMTUD can tolerate multiple lost probes before treating a probe size as failed.
• Added accept_with_retry() and RetryConnectionIds, allowing servers to use a fresh connection source connection ID that is distinct from the Retry source connection ID.
• Improved qlog congestion metrics with Cloudflare-specific delivery, send, and ACK rate values in MetricsUpdated.ex_data.
• Fixed in-handshake recovery and configuration overrides so they still apply after ACK-only packets in multi-packet handshakes.
• Other bug fixes and performance improvements.

Full changelog at 0.24.9...0.25.0