[FIX] it is possible that temporary NSManagedObjects get created with a nil context, in which case the desiredConcurrencyIdentifier may be nil, even though correct concurrency is being respected
[FIX] it is possible that temporary NSManagedObjects get created with a nil context, in which case the desiredConcurrencyIdentifier may be nil, even though correct concurrency is being respected

zhaoguohui/GDCoreDataConcurrencyDebugging,GrahamDennis/GDCoreDataConcurrencyDebugging,rokgregoric/GDCoreDataConcurrencyDebugging