Sometimes, exporting images isn't easy

UIKitExportEnv.cs

	public class UIKitExportEnv : ExportEnv
	{
		public UIKitExportEnv (string name, Model model)
			: base (name, model)
		{
		}
		
		protected override void WriteTexture (ITexture texture, ExportedFile file)
		{
			var width = texture.Width;
			var height = texture.Height;
			
			using (var imageContext = texture.CreateContext ()) {
				using (var image = imageContext.ToImage ()) {
					using (var renderContext = texture.CreateContextWithData (IntPtr.Zero)) {
						
						renderContext.TranslateCTM (0, height);
						renderContext.ScaleCTM (1, -1);
						renderContext.DrawImage (new RectangleF (0, 0, width, height), image);
						
						using (var render = renderContext.ToImage ()) {
							using (var uiImage = new UIImage (render)) {
								using (var data = uiImage.AsPNG ()) {
									unsafe {
										using (var s = new UnmanagedMemoryStream ((byte*)data.Bytes, data.Length)) {
											s.CopyTo (file.Stream);
										}
									}
								}
							}
						}
					}
				}
			}
		}
	}