UIScrollview 滑动到边界的时候整个视图连带滑动效果

效果：

2019-11-07 09-24-42.2019-11-07 09_25_03.gif

代码：

-(void)scrollViewDidScroll:(UIScrollView *)scrollView{

    if(self.tableView.contentOffset.y <= 0){
        scrollView.contentOffset = CGPointMake(0, 0);
        [self panEvent:scrollView.panGestureRecognizer];
    }
}

-(void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{
    [self panEvent:scrollView.panGestureRecognizer];
}

-(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{
    [self panEvent:scrollView.panGestureRecognizer];
}

- (void)panEvent:(UIPanGestureRecognizer *)sender{

    static CGFloat beginOffset = 0;
    
    if(sender.state == UIGestureRecognizerStateChanged){
            
        CGPoint offset = [sender translationInView:self.view];
        
        if(offset.y > 0){
            self.tableView.transform = CGAffineTransformMakeTranslation(0, offset.y-beginOffset);
        }
    }
    
    if(sender.state == UIGestureRecognizerStateEnded){
        beginOffset = 0;
        [UIView animateWithDuration:0.2 animations:^{
            self.tableView.transform = CGAffineTransformIdentity;
        }];
    }
    
    if(sender.state == UIGestureRecognizerStateBegan){
        beginOffset = self.tableView.contentOffset.y;
    }
}