'Resolve the hostname string into a tuple containing the host
address.  This is method is only used when the reactor does
not provide L{IReactorPluggableNameResolver}.
@param host: A unicode hostname to resolve.
@param port: The port to include in the resolution.
@return: A L{Deferred} that fires with L{_getaddrinfo}\'s
return value.'

def _fallbackNameResolution(self, host, port):

    return self._deferToThread(self._getaddrinfo, host, port, 0, socket.SOCK_STREAM)
