title: On iOS, what are the differences between margins, edge insets, content insets, alignment rects, layout margins, anchors...?
body: <p>There seem to be several different options/terms and people in the iOS community use with respect to layout (e.g. UIEdgeInsets is a type, but sometimes I hear/read "set the insets" or layout margins vs layout guides). </p>
  
  <p>I've always been able to find an option that works.  But I'm never sure that I'm using the right tool for the job.</p>
  
  <p>Can someone help provide some clarity between these different aspects of layout and when to use each in the best way?</p>