private static Stream GetTileStream(TileIndex index)
{
var path = $"Mapsui.Tests.Common.Resources.SampleTiles.{index.Level}_{index.Col}_{index.Row}.png";
var data = typeof(Utilities).GetTypeInfo().Assembly.GetManifestResourceStream(path);
if (data == null) throw new Exception($"Resource could not be found: {path}");
return data;
}