---
prelude: >
    This release includes optional support for fair locks.  When fair locks
    are specified, blocking waiters will acquire the lock in the order that
    they blocked.
features:
  - |
    We now have optional support for ``fair`` locks.  When fair locks are
    specified, blocking waiters will acquire the lock in the order that they
    blocked.  This can be useful to ensure that existing blocked waiters do
    not wait indefinitely in the face of large numbers of new attempts to
    acquire the lock.  When specifying locks as both ``external`` and ``fair``,
    the ordering *within* a given process will be fair, but the ordering
    *between* processes will be determined by the behaviour of the underlying
    OS.