Fix memory leaks

• [BUGFIX] Memory leak in IETF full conn dtor: cleanup closed IDs sets.
• [BUGFIX] Memory leak: free pushed promise when refcnt is zero.

Minor bug fix; some refactoring

• [BUGFIX] Typo in new "validate peer addr by DCID" code. It is a benign bug (works either way), but better to fix it.
• Simplify Stream Priority Iterator (SPI).
• Minor documentation updates.

Features: ID-30, datagrams, adaptive CC support; bug fixes

• [FEATURE] QUIC and HTTP/3 Internet Draft 30 support.
• [FEATURE] Unreliable Datagram Extension support.
• [FEATURE] Adaptive congestion controller.
• [BUGFIX] Do not send MAX_STREAM_DATA frames on crypto streams.
• [BUGFIX] Fail with CRYPTO_BUFFER_EXCEEDED when too much CRYPTO data comes in.
• [BUFFIX] Spin bit is now strictly per path; value is reset on DCID change.
• [BUGFIX] Check that max value of max_streams_uni and max_streams_bidi TPs is 2^60.
• [BUGFIX] Close IETF mini conn immediately if crypto session cannot be initialized.
• Deprecate ID-28 (no browser uses it): it's no longer in the default versions list.
• New programs duck_server and duck_client that implement the experimental siduck-00 protocol. They quack!
• IETF crypto streams: don't limit ourselves from sending.
• Command-line programs: turn off QL loss bits if -G is used, as Wireshark cannot decrypt QUIC packets when this extension is used.
• Turn all h3 framing unit tests back on.
• Fix malo initialization when compiled in no-pool mode.

Feature: pwritev; bug fixes

• [FEATURE] Add lsquic_stream_pwritev(). This function allows one to reduce the number of system calls required to read a file from disk by using lsquic_stream_pwritev() together with preadv(2).
• [BUGFIX] When stream is reset, it is writeable -- let user collect the error.
• [BUGFIX] Calculate correct conn flow control if reading ends early.
• [BUGFIX] Remove stream from read and write queues on internal shutdown. This is a regression introduced in 2.19.7.
• [BUGFIX] Swapped arguments in IETF RESET_FRAME generation.
• Turn off mini conn history when compiling with Visual Studio; this allows the project to compile on Windows again.
• http_client: Add -3 flag to stop reading from streams early; code cleanup.
• Don't use -Werror.

Bug fix: when stream is reset, it is writeable

v2.12.8

Update version to 2.12.8

ECN blackholes, new timestamps, and bug fixes

• [FEATURE] Update the timestamp extension to latest version.
• [FEATURE] Cope with appearance of ECN blackholes.
• [OPTIMIZATION] return packno offset and size when header is generated.
• [BUGFIX] ignore old ACK frames in mini conns.
• [BUGFIX] Mark initial server path as initialized.
• [BUGFIX] Do not merge ACK if ECN counts do not match.
• Turn incoming packet number history in mini conn back on.
• Record mini conn event history again when compiled in debug mode.
• IETF mini conn: log when ACK is queued.
• Clean up and refactor code in several places.

Fixes and tying up of loose ends

• Handle ECT-CE event: issue a loss event.
• Log the fact that we ignore SETTINGS_MAX_HEADER_LIST_SIZE.
• Use Max Push ID in GOAWAY frame to cancel promises.
• Add support for HTTP/3 CANCEL_PUSH frame.
• lsquic_stream_is_pushed: streams without headers are never pushed.
• [BUGFIX] Regression in lsquic_stream_shutdown_internal: now it shuts down.
• Improve logic whether to generate CONNECTION_CLOSE.

Minor ECN improvements

• Don't process incoming ECN marks if ECN is not enabled.
• Schedule ACK when incoming packet is marked with CE.

Bugfix release: DPLPMTUD stealing ACK across buffered packets

• [BUGFIX] Generate frame record when moving an ACK from one buffered packet to another.

Bugfix release: DPLPMTUD

• [BUGFIX] Do not return an oversize MTU probe to connection twice.
• [FEATURE] Delayed Acks updated to latest draft. Still experimental.
• Minor code cleanup in IETF full connection.