Small issue I ran into while doing some stubbing of reachability in offline mode. After a call to stopMonitoringNetworkReachability, the _networkReachability is not set to NULL after being handed to CFRelease. If another call path tries to stop the monitoring again, you hit a crash attempting to work with the deallocated object instance.
Present in master as of f0e6b53
Set `_networkReachability` to `NULL` after releasing. fixes AFNetwork…
Fixed by b43345b.