def get_http_connection(self, host, is_secure):
        """
        Gets a connection from the pool for the named host.  Returns
        None if there is no connection that can be reused.
        """
        if is_secure:
            return AsyncHTTPSConnection(host, http_client=self._httpclient)
        else:
            return AsyncHTTPConnection(host, http_client=self._httpclient)
Gets a connection from the pool for the named host.  Returns
        None if there is no connection that can be reused.