librdkafka v1.8.0

librdkafka v1.8.0 is a security release:

Upgrade bundled zlib version from 1.2.8 to 1.2.11 in the librdkafka.redist
NuGet package. The updated zlib version fixes CVEs:
CVE-2016-9840, CVE-2016-9841, CVE-2016-9842, CVE-2016-9843
See #2934 for more information.
librdkafka now uses vcpkg for up-to-date Windows
dependencies in the librdkafka.redist NuGet package:
OpenSSL 1.1.1l, zlib 1.2.11, zstd 1.5.0.
The upstream dependency (OpenSSL, zstd, zlib) source archive checksums are
now verified when building with ./configure --install-deps.
These builds are used by the librdkafka builds bundled with
confluent-kafka-go, confluent-kafka-python and confluent-kafka-dotnet.

Enhancements

Producer flush() now overrides the linger.ms setting for the duration
of the flush() call, effectively triggering immediate transmission of
queued messages. (#3489)

Correctly detect presence of zlib via compilation check. (Chris Novakovic)
ERR__ALL_BROKERS_DOWN is no longer emitted when the coordinator
connection goes down, only when all standard named brokers have been tried.
This fixes the issue with ERR__ALL_BROKERS_DOWN being triggered on
consumer_close(). It is also now only emitted if the connection was fully
up (past handshake), and not just connected.
rd_kafka_query_watermark_offsets(), rd_kafka_offsets_for_times(),
consumer_lag metric, and auto.offset.reset now honour
isolation.level and will return the Last Stable Offset (LSO)
when isolation.level is set to read_committed (default), rather than
the uncommitted high-watermark when it is set to read_uncommitted. (#3423)
SASL GSSAPI is now usable when sasl.kerberos.min.time.before.relogin
is set to 0 - which disables ticket refreshes (by @mpekalski, #3431).
Rename internal crc32c() symbol to rd_crc32c() to avoid conflict with
other static libraries (#3421).
txidle and rxidle in the statistics object was emitted as 18446744073709551615 when no idle was known. -1 is now emitted instead. (#3519)

Automatically retry offset commits on ERR_REQUEST_TIMED_OUT,
ERR_COORDINATOR_NOT_AVAILABLE, and ERR_NOT_COORDINATOR (#3398).
Offset commits will be retried twice.
Timed auto commits did not work when only using assign() and not subscribe().
This regression was introduced in v1.7.0.
If the topics matching the current subscription changed (or the application
updated the subscription) while there was an outstanding JoinGroup or
SyncGroup request, an additional request would sometimes be sent before
handling the response of the first. This in turn lead to internal state
issues that could cause a crash or malbehaviour.
The consumer will now wait for any outstanding JoinGroup or SyncGroup
responses before re-joining the group.
auto.offset.reset could previously be triggered by temporary errors,
such as disconnects and timeouts (after the two retries are exhausted).
This is now fixed so that the auto offset reset policy is only triggered
for permanent errors.
The error that triggers auto.offset.reset is now logged to help the
application owner identify the reason of the reset.
If a rebalance takes longer than a consumer's session.timeout.ms, the
consumer will remain in the group as long as it receives heartbeat responses
from the broker.

DeleteRecords() could crash if one of the underlying requests
(for a given partition leader) failed at the transport level (e.g., timeout).
(#3476).

Release asset checksums:

v1.8.0.zip SHA256 4b173f759ea5fdbc849fdad00d3a836b973f76cbd3aa8333290f0398fd07a1c4
v1.8.0.tar.gz SHA256 93b12f554fa1c8393ce49ab52812a5f63e264d9af6a50fd6e6c318c481838b7f