同步调用NSView的好方法是什么?

-(void)setImageBuffer:(unsigned char*)buffer
{
    /* image handling stuff; thread-safe */

    [self performSelectorOnMainThread:@selector(induceRedraw)
                           withObject:nil
                                      // Don't just copy this; pick one...
                        waitUntilDone:YES or NO];
}

-(void)induceRedraw
{
    [self setNeedsDisplay:YES]; // but this is not thread-safe
}

dispatch_queue_t q = dispatch_get_main_queue();
dispatch_async(q, ^(void) {
  [self setNeedsDisplay: YES];
});