title: How to distinguish between custom and "built-in" fonts in iOS?
body: <p>I have included several Google Fonts ttf files in my iOS project as custom fonts.  Everything works and I can use the fonts fine.  However, I need to distinguish between custom fonts and those automatically provided by iOS.  </p>
  
  <p>I have tried comparing filenames returned by UIFont.FontNamesForFamilyName with the fonts' filenames in the Info.plist file.  Although it works for most fonts, the filenames don't always match the font names; some may have underscores or dashes in them.  Since I can't rely on the filename to be exact, what other options do I have?</p>