title: How to figure out meaningful feature index for mesh triangle in ARSCNFaceGeometry
body: <p>Working in ARKit using ARSCNFaceGeometry I understand there are over 1000 feature indices.</p>
  
  <p>I understand that there are hard-coded mesh indices for example "9" for nose. "42" for right eye etc. </p>
  
  <p>But is there a detailed list of indices so I can work with specific parts of the face?</p>
  
  <p>Additionally, there are comments everywhere that working with hardcoded indices is not future proof I could not find a viable alternative.</p>