'@see: L{INegotiated.negotiatedProtocol}'

@property
def negotiatedProtocol(self):

    protocolName = None
    try:
        protocolName = self._tlsConnection.get_alpn_proto_negotiated()
    except (NotImplementedError, AttributeError):
        pass
    if (protocolName not in ('', None)):
        return protocolName
    try:
        protocolName = self._tlsConnection.get_next_proto_negotiated()
    except (NotImplementedError, AttributeError):
        pass
    if (protocolName != ''):
        return protocolName
    return None
