title: Can I change multiplier property for NSLayoutConstraint?
body: <p>I created two views in one superview, and then added constraints between views:</p>
  
  <pre><code>_indicatorConstrainWidth = [NSLayoutConstraint constraintWithItem:self.view1 attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:self.view2 attribute:NSLayoutAttributeWidth multiplier:1.0f constant:0.0f];
  [_indicatorConstrainWidth setPriority:UILayoutPriorityDefaultLow];
  _indicatorConstrainHeight = [NSLayoutConstraint constraintWithItem:self.view1 attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:self.view2 attribute:NSLayoutAttributeHeight multiplier:1.0f constant:0.0f];
  [_indicatorConstrainHeight setPriority:UILayoutPriorityDefaultLow];
  [self addConstraint:_indicatorConstrainWidth];
  [self addConstraint:_indicatorConstrainHeight];
  </code></pre>
  
  <p>Now I want to change multiplier property with animation, but I can't figure out how to change the multipler property. (I found _coefficient in private property in header file NSLayoutConstraint.h, but it private.)</p>
  
  <p>How do I change multipler property? </p>
  
  <p>My workaround is to remove the old constraint and add the new one with a different value for <code>multipler</code>.</p>