'Sets up the host and the port for the HTTP CONNECT Tunnelling.'

def set_tunnel(self, host, port):

    url = host
    if port:
        url = ((url + u':') + port)
    var_host = VARIANT.create_bstr_from_str(url)
    var_empty = VARIANT.create_empty()
    _WinHttpRequest._SetProxy(self, HTTPREQUEST_PROXYSETTING_PROXY, var_host, var_empty)
