``` objc[763]: +[__NSPlaceholderArray initialize] may have been in progress in another thread when fork() was called. objc[763]: +[__NSPlaceholderArray initialize] may have been in progress in another thread when fork() was called. We cannot safely call it or ignore it in the fork() child process. Crashing instead. Set a breakpoint on objc_initializeAfterForkError to debug. ```