internal void Init(ProgressStream stream, long totalBytes, IProgress <WebDavProgress> progress)
 {
     this.totalBytes     = totalBytes;
     stream.ReadCallback = ReadBytes;
     this.progress       = progress;
 }
 internal WebDavProgressStreamContent(ProgressStream stream, long totalBytes, int bufferSize, IProgress <WebDavProgress> progress)
     : base(stream, bufferSize)
 {
     Init(stream, totalBytes, progress);
 }