This release adds a couple of new features:

• Adds an API to peek stream data on ReceiveStream and Stream: #5501
• Adds an API to peek the next varint on a stream: #5502
• Reworks the API exposed by the HTTP/3 package for WebTransport: #5509, #5512. Regular HTTP/3 use cases should not be affected by these changes.
• Adds support for HTTP request trailers (trailers sent by the client): #5507

Breaking Changes

• Removes the deprecated ClientHelloInfo: #5497
• Removes the deprecated ConnectionTracingID and ConnectionTracingKey: #5521
• http3: the qlogger is now closed after all streams have been handled: #5524
• The ConnectionState now reports both the local and the remote status of the QUIC Datagram and Reliable Stream Reset extensions: #5533

Other Notable Fixes

• Fixes an infinite loop of PING-only packets caused by a bug in the PTO queueing logic: #5538 and #5539
• http3: Fixes a race condition between new request streams and GOAWAY: #5522
• qlog: Fixes a race condition between RecordEvent and Close: #5523

Changelog

• remove deprecated ClientHelloInfo by @marten-seemann in https://github.com/quic-go/quic-go/pull/5497
• expose SetReliableBoundary method on the Stream by @marten-seemann in https://github.com/quic-go/quic-go/pull/5498
• simplify ReceiveStream.Read implementation by @marten-seemann in https://github.com/quic-go/quic-go/pull/5500
• ci: use codecov-action instead of codecov/test-results-action by @Copilot in https://github.com/quic-go/quic-go/pull/5504
• http3: add support for request trailers by @marten-seemann in https://github.com/quic-go/quic-go/pull/5507
• http3: remove stream hijacking API by @marten-seemann in https://github.com/quic-go/quic-go/pull/5508
• http3: remove Hijacker, add Settingser interface by @marten-seemann in https://github.com/quic-go/quic-go/pull/5509
• implement a stream peeking API by @marten-seemann in https://github.com/quic-go/quic-go/pull/5501
• ci: fix Codecov upload by untracking integrationtests before removal by @marten-seemann in https://github.com/quic-go/quic-go/pull/5511
• quicvarint: implement function to peek the next varint by @marten-seemann in https://github.com/quic-go/quic-go/pull/5502
• http3: implement new API to allow fine-grained control of connections by @marten-seemann in https://github.com/quic-go/quic-go/pull/5512
• remove deprecated ConnectionTracingID and ConnectionTracingKey by @marten-seemann in https://github.com/quic-go/quic-go/pull/5521
• http3: fix race between new streams and GOAWAY by @marten-seemann in https://github.com/quic-go/quic-go/pull/5522
• qlogwriter: fix race between RecordEvent and Close by @marten-seemann in https://github.com/quic-go/quic-go/pull/5523
• polish the security policy by @marten-seemann in https://github.com/quic-go/quic-go/pull/5526
• http3: close qlogger after all streams have been handled by @marten-seemann in https://github.com/quic-go/quic-go/pull/5524
• fix flaky TestHTTP3Qlog by @marten-seemann in https://github.com/quic-go/quic-go/pull/5532
• expose local and remote settings in ConnectionState by @marten-seemann in https://github.com/quic-go/quic-go/pull/5533
• ackhandler: fix qlogging of outstanding packet count by @marten-seemann in https://github.com/quic-go/quic-go/pull/5538
• ackhandler: fix counting of packets queued for PTO probing by @marten-seemann in https://github.com/quic-go/quic-go/pull/5539

Full Changelog: https://github.com/quic-go/quic-go/compare/v0.58.0...v0.59.0