Release 3.1.0

Release 2.27.1

- [API] New knob to set outgoing packet batch size.
- Aborted connection now become tickable immediately.
- Abort connection when HTTP/3 frame cannot be opened (can only happen
when malloc fails).

Release 2.19.0

- [FEATURE] DPLPMTUD support. IETF connections now search for the
maximum packet size, improving throughput.
- [DEBUG] Record event in stream history when on_close() is called
in dtor.

Release 2.13.0

- [API] Use lsxpack_header structure to process incoming headers.
- [BUGFIX] Fix assertion when zero-padding Initial packet.
- [BUGFIX] Use idle timeout before we learn of peer's value.
- Use ls-hpack 2.0.0 -- has lsxpack_header changes.
- Use ls-qpack 0.14.0 -- new, common with ls-hpack, XXH seed (not used yet).
- Code cleanup: prefix exported functions with "lsquic_".

Release 2.8.7

- [BUGFIX] Initial packet size check for IETF mini conn applies to
UDP payload, not QUIC packet.
- Support old and new school loss_bits transport parameter.
- Use Q run length of 64 as suggested in the loss bits Draft.
- Undo square wave count when packet is delayed.
- Code cleanup; minor fixes.

Release 2.2.0: server included, ID-22 supported (#76)

Release 1.18.0

- [API Change] Can specify clock granularity in engine settings.
- [BUGFIX] Pacer uses fixed clock granularity. Since the change on
2018-04-09, it is not necessary to try to approximate the next tick
time in the pacer: it can use fix clock granularity specified by
the user.
- [BUGFIX] Do not tick constantly before handshake is done.
- [BUGFIX] Do not exit tick prematurely: reuse packet with ACK. Even
if we cannot allocate *more* packets, we could still be able to write
to one already allocated.
- [BUGFIX] Do not schedule pacer if there are no lost packets.

Release 1.17.11

Fix strict aliasing warning in when compiling with optimizations

[API Change, OPTIMIZATION] Only process conns that need to be processed

The API is simplified: do not expose the user code to several
queues. A "connection queue" is now an internal concept.
The user processes connections using the single function
lsquic_engine_process_conns(). When this function is called,
only those connections are processed that need to be processed.
A connection needs to be processed when:

1. New incoming packets have been fed to the connection.
2. User wants to read from a stream that is readable.
3. User wants to write to a stream that is writeable.
4. There are buffered packets that can be sent out. (This
means that the user wrote to a stream outside of the
lsquic library callback.)
5. A control frame (such as BLOCKED) needs to be sent out.
6. A stream needs to be serviced or delayed stream needs to
be created.
7. An alarm rings.
8. Pacer timer expires.

To achieve this, the library places the connections into two
priority queues (min heaps):

1. Tickable Queue; and
2. Advisory Tick Time queue (ATTQ).

Each time lsquic_engine_process_conns() is called, the Tickable
Queue is emptied. After the connections have been ticked, they are
queried again: if a connection is not being closed, it is placed
either in the Tickable Queue if it is ready to be ticked again or
it is placed in the Advisory Tick Time Queue. It is assumed that
a connection always has at least one timer set (the idle alarm).

The connections in the Tickable Queue are arranged in the least
recently ticked order. This lets connections that have been quiet
longer to get their packets scheduled first.

This change means that the library no longer needs to be ticked
periodically. The user code can query the library when is the
next tick event and schedule it exactly. When connections are
processed, only the tickable connections are processed, not *all*
the connections. When there are no tick events, it means that no
timer event is necessary -- only the file descriptor READ event
is active.

The following are improvements and simplifications that have
been triggered:

- Queue of connections with incoming packets is gone.
- "Pending Read/Write Events" Queue is gone (along with its
history and progress checks). This queue has become the
Tickable Queue.
- The connection hash no longer needs to track the connection
insertion order.

Update copyright year; add CONTRIBUTORS.txt

Latest changes

- [API Change] lsquic_engine_connect() returns pointer to the connection
object.
- [API Change] Add lsquic_conn_get_engine() to get engine object from
connection object.
- [API Change] Add lsquic_conn_status() to query connection status.
- [API Change] Add add lsquic_conn_set_ctx().
- [API Change] Add new timestamp format, e.g. 2017-03-21 13:43:46.671345
- [OPTIMIZATION] Process handshake STREAM frames as soon as packet
arrives.
- [OPTIMIZATION] Do not compile expensive send controller sanity check
by default.
- [OPTIMIZATION] Add fast path to gquic_be_gen_reg_pkt_header.
- [OPTIMIZATION] Only make squeeze function call if necessary.
- [OPTIMIZATION] Speed up Q039 ACK frame parsing.
- [OPTIMIZATION] Fit most used elements of packet_out into first 64 bytes.
- [OPTIMIZATION] Keep track of scheduled bytes instead of calculating.
- [OPTIMIZATION] Prefetch next unacked packet when processing ACK.
- [OPTIMIZATION] Leverage fact that ACK ranges and unacked list are.
ordered.
- [OPTIMIZATION] Reduce function pointer use for STREAM frame generation
- Fix: reset incoming streams that arrive after we send GOAWAY.
- Fix: delay client on_new_conn() call until connection is fully set up.
- Fixes to buffered packets logic: splitting, STREAM frame elision.
- Fix: do not dispatch on_write callback if no packets are available.
- Fix WINDOW_UPDATE send and resend logic.
- Fix STREAM frame extension code.
- Fix: Drop unflushed data when stream is reset.
- Switch to tracking CWND using bytes rather than packets.
- Fix TCP friendly adjustment in cubic.
- Fix: do not generate invalid STOP_WAITING frames during high packet
loss.
- Pacer fixes.

LSQUIC Client: Initial release