Get the specific Header value, as an <code>int</code>, from the Upgrade Request.
@param name the name of the header
@return the value of the header as an <code>int</code> (-1 if header does not exist)
@throws NumberFormatException if unable to parse value as an int.
Get the specific Header value, as an <code>int</code>, from the Upgrade Request.
@param name the name of the header @return the value of the header as an <code>int</code> (-1 if header does not exist) @throws NumberFormatException if unable to parse value as an int.