Any raw assets you want to be deployed with your application can be placed in
  this directory (and child directories) and given a Build Action of "AndroidAsset".
  
  These files will be deployed with you package and will be accessible using Android's
  AssetManager, like this:
  
  public class ReadAsset : Activity
  {
          protected override void OnCreate (Bundle bundle)
          {
                  base.OnCreate (bundle);
  
                  InputStream input = Assets.Open ("my_asset.txt");
          }
  }
  
  Additionally, some Android functions will automatically load asset files:
  
  Typeface tf = Typeface.CreateFromAsset (Context.Assets, "fonts/samplefont.ttf");