private void TryUpdateContentLength(string str)
{
int pos1 = str.LastIndexOf("(");
if (pos1 != -1)
{
int pos2 = str.IndexOf(" bytes).");
if (pos2 != -1 && pos2 > pos1)
{
pos1++;
long result;
if (Int64.TryParse(str.Substring(pos1, pos2 - pos1),
NumberStyles.AllowLeadingWhite | NumberStyles.AllowTrailingWhite,
NumberFormatInfo.InvariantInfo, out result))
{
_contentLength = result;
}
}
}
}