FileLoader

HttpWebRequest checkedRequest = (HttpWebRequest) WebRequest.Create(remoteFilename);
HttpWebResponse checkedResponse = (HttpWebResponse) checkedRequest.GetResponse();
FileStream fs = new FileStream(localFilename, FileMode.OpenOrCreate);
request = (HttpWebRequest)WebRequest.Create(remoteFilename);

if (fs.Length < checkedResponse.ContentLength && fs.Length != 0)
{
  request.Headers.Add("range", $"bytes={fs.Length}-");
  }
            
response = (HttpWebResponse)request.GetResponse();
long downloadFileSize = response.ContentLength;
Stream s = response.GetResponseStream();

long startNumByte = 0;
            
if (fs.Length != 0)
  startNumByte = fs.Length;
Console.WriteLine(((double) (checkedResponse.ContentLength - fs.Length) / 1024 / 1024).ToString("0.0 МБ"));
Byte[] read = new byte[checkedResponse.ContentLength - fs.Length];
long iRunningByteTotal = startNumByte;
            
int count = s.Read(read, 0, 1024);
            
iRunningByteTotal += count;
long totalSize = checkedResponse.ContentLength;

while (count > 0) 
{ 
  fs.Write(read, 0, count);
  count = s.Read(read, 0, 1024);
  
  iRunningByteTotal += count;
}

fs.Close(); 
s.Close();
response.Close();