public async Task DownloadTest4_LoadOnlyImageInfo()
{
var imgUrl = "https://raw.githubusercontent.com/cs-util-com/cscore/master/CsCore/assets/logo-cscore1024x1024_2.png";
var h = 1024;
var w = 1024;
var timingForFullImage = Log.MethodEntered("Load full image");
var fullImage = await new Uri(imgUrl).SendGET().GetResult <Stream>();
var info2 = await ImageLoader.GetImageInfoFrom(fullImage);
fullImage.Dispose();
Assert.Equal(h, info2.Height);
Assert.Equal(w, info2.Width);
Log.MethodDone(timingForFullImage);
var timingForImageInfoOny = Log.MethodEntered("Load only first bytes");
var stream = await new Uri(imgUrl).SendGET().GetResult <Stream>();
var firstBytes = await ImageLoader.CopyFirstBytes(stream, bytesToCopy : 500);
Assert.True(firstBytes.CanSeek);
var info = await ImageLoader.GetImageInfoFrom(firstBytes);
firstBytes.Dispose();
Assert.Equal(w, info.Width);
Assert.Equal(h, info.Height);
Log.MethodDone(timingForImageInfoOny);
stream.Dispose();
var xTimesFaster = 3; // Loading only the image info should be at least this factor faster then loading the full image
string e = $"{timingForImageInfoOny} was not {xTimesFaster} times faster then {timingForFullImage}!";
Assert.True(timingForImageInfoOny.ElapsedMilliseconds * xTimesFaster < timingForFullImage.ElapsedMilliseconds, e);
}