Solution: bump back from 4.3.1 to 4.3.0

* Add ZMQ_ROUTER_NOTIFY draft socket option

Solution: move them from DRAFT state to STABLE

Solution: define and apply parameter naming style: lower_case_

Solution: add a new ZMQ_MULTICAST_LOOP option for UDP sockets.

Solution: revert the revert!

Revert "Problem: regression in 4.2.3 went unnoticed, want to release 4.2.5"

This reverts commit 5f17e26f.

Solution: revert DRAFT -> STABLE API transition so that we can do a
bugfix-only 4.2.5 release.
Will be re-reverted once tagged.

Revert "Problem: ZMQ_BINDTODEVICE has met STABLE conditions"

This reverts commit 3cb79f50.

Revert "Problem: ZMQ_MSG_GSSAPI_* have met STABLE conditions"

This reverts commit 374da420.

Revert "Problem: ZMQ_MSG_T_SIZE has met STABLE conditions"

This reverts commit 6411c4a2.

Revert "Problem: docs say STABLE API still in DRAFT"

This reverts commit 9f2f30b7.

Solution: move them from DRAFT to STABLE since it's been in a public
release, committed for 6+ months and has not changed.

Solution: move them from DRAFT to STABLE since it's been in a public
release, committed for 6+ months and has not changed.

Solution: move it from DRAFT to STABLE since it's been in a public
release, committed for 6+ months and has not changed.
Given a new STABLE symbol has been added, bump minor version number.

Solution: bump to 4.2.5

Lets the application set per-connection metadata.
Metadata is specified as "X-key:value" and set using zmq_setsockopt, eg:
zmq_setsockopt (s, ZMQ_METADATA, "X-key:value", 11);

The peer can then obtain the metadata from a received message:
char *data = zmq_msg_gets(msg, "X-key");

The zero copy decoding strategy implemented for 4.2.0 can lead to a large
increase of main memory usage in some cases (I have seen one program go up to
40G from 10G after upgrading from 4.1.4). This commit adds a new option to
contexts, called ZMQ_ZERO_COPY_RECV, which allows one to switch to the old
decoding strategy.

Solution: add socket option

Solution: relaxed test assertions, based on the actual time passed,
instead of assuming that this equals to the time slept

Solution: applied clang-format

Solution: bump changelog, ABI revision, library and packaging version

Solution: remove it

Change ZMQ_THREAD_AFFINITY to ZMQ_THREAD_AFFINITY_CPU_ADD/ZMQ_THREAD_AFFINITY_CPU_REMOVE. Avoid prefix thread names when no prefix was set.

* Add ZMQ_THREAD_NAME_PREFIX ctx option

* Background thread scheduling 

- add ZMQ_THREAD_AFFINITY ctx option; set all thread scheduling options
from the context of the secondary thread instead of using the main
process thread context!
- change ZMQ_THREAD_PRIORITY to support setting NICE of the background
thread when using SCHED_OTHER

Solution: add ZMQ_ZAP_ENFORCE_DOMAIN to hide backward incompatible
change and make it disabled by default.
In a future release that breaks API compatibility we can then switch
the default to enabled in order to achieve full RFC compatibility.

Fixes #2762

Solution: Renamed, but support querying the property by its old name

Solution: renamed routing_id fields in pipe_t, renamed ZMQ_CONNECT_RID to ZMQ_CONNECT_ROUTING_ID

Solution: replace by "routing id"

Solution: Renamed, but support querying the property by its old name

Solution: renamed routing_id fields in pipe_t, renamed ZMQ_CONNECT_RID to ZMQ_CONNECT_ROUTING_ID

Solution: replace by "routing id"

Solution: added test case (with dummy implementation of zmq_socket_get_peer_state)

Solution: move them together with the other DRAFT socket options, and
change value of DRAFT ZMQ_BINDTODEVICE from 90 to 92 to avoid clash

Solution: add handshake failure events to curve_client_t

Solution: emit socket monitor events for NULL protocol errors (like CURVE)

Solution: redesign ZMQ_HANDSHAKE_FAILED_* events, introduce new class of ZMQ_HANDSHAKE_FAILED_AUTH events

uint32_t is used in the draft APIs
and undefined on MSC 1500
preventing compilation

Solution: Define them in zmq.h and use them (currently in DRAFT API)