file.m

dispatch_sync(dispatch_get_main_queue(), ^{
                    if ([event timestamp] != 1) {
                        [super sendEvent: [NSEvent keyEventWithType:NSEventTypeKeyDown
                                                           location:[event locationInWindow]
                                                      modifierFlags:[event modifierFlags]
                                                          timestamp:1
                                                       windowNumber:[event windowNumber]
                                                            context:nil
                                                         characters:[event characters]
                                        charactersIgnoringModifiers:[event charactersIgnoringModifiers]
                                                          isARepeat:[event isARepeat]
                                                            keyCode:[event keyCode]]];
                    }
                });