Most frightening piece of code I've ever seen

PDFView.m

- (void)
dealloc 
{
    // because of TiledLayer ( which draws in a separate threads) and propbably a bug in iOS  dealloc is called twice. 
    // make sure it will execute once in our class
    if ( _deallocCalled )
        return;

    _deallocCalled = YES;
    
#if XXXXXX
    usleep(50000);
#endif
    
    [self disableDrawing];
    
    CGPDFDocumentRelease(pdf);
    pdf = NULL;
    
    [_lockPdfDrawers lock];
    [_lockPdfDrawers unlock];
    [_lockPdfDrawers release];
    _lockPdfDrawers = nil;
    
#if XXXXXX
    usleep(200000); //wait 200 milliseconds
#endif 
    
  [super dealloc];
}