public void DownloadedBetween()
{
var dp = new DownloadProgress();
dp.Download(0, 10);
dp.Download(20, 10);
dp.Download(40, 10);
dp.Download(60, 10);
Assert.AreEqual(dp.Downloaded, dp.DownloadedBetween(0, 70));
Assert.AreEqual(20, dp.DownloadedBetween(0, 30));
Assert.AreEqual(10, dp.DownloadedBetween(5, 20));
dp.Download(0, 70);
Assert.AreEqual(30, dp.DownloadedBetween(0, 30));
}