3.5.2 - 2021-02-23
    * Fixed a very rare potential inter-thread race on daemon shutdown due to a
      'stop' or 'replace'.  If a still-in-progress zone reload operation had
      started just before the stop/replace, and happened to finish its job at
      nearly the exact same moment that the main thread was deallocating the
      zone data, both the reloader thread and the main thread could attempt to
      deallocate it at the same time.  This happens after DNS listeners are
      stopped, but it's still an unclean crash instead of a clean termination.
      In the 'replace' case it would also cause the new daemon to get no stats
      data handoff thanks to the crash (but the new daemon would still
      successfully start).  This issue hasn't ever been observed or reported in
      the wild, but I'm pretty sure it was possible with some extremely low
      probability.
    * The timeout for some control socket network operations between two
      daemons during a 'replace' takeover was extended from a fixed 13s to a
      fixed 37s.  There is no perfect value here that balances all concerns
      without adding a ton of new code complexity, but this new value should be
      more robust in edge cases in practice.  Making it configurable for those
      with known edge cases would be an easy next step!
    * Fixed an snprintf format bug that effectively limited stats outputs to
      32-bit counters on x86_64 x32 ABI builds, even though they were being
      tracked as 64-bit internally.
    * Fixed a minor snprintf format bug in a log message about very early
      failures in zonefile processing, which probably wasn't causing any real
      bug on most platforms
    * Hopefully improved the reliability of the 011random.t test on hosts
      that are slower and/or have smaller default UDP receive buffers.
    * Added a docs and log warning about not relying on the default 'any'
      listen option without explicitly requesting it, for compat with future
      versions.
    * Relaxed a constraint in the socket handoff process between daemons
      during 'replace' in the interest of compat with future versions.
    * Added some additional pedantic safety measures to how TCP thread
      shutdowns are sequenced.
    * Improved the utility and/or accuracy of various error log messages
    * A few small code QA nits of no real consequence