How to use the fabric-protos.common.Envelope function in fabric-protos

const configUpdate = new common.ConfigUpdate({ channel_id: channelName, read_set: readSet, write_set: writeSet});
        const configUpdateEnv= new common.ConfigUpdateEnvelope({ config_update: configUpdate.toBuffer(), signatures: [] });

        // Channel header
        const channelTimestamp = new google.protobuf.Timestamp({ seconds: Date.now()/1000, nanos: 0 }); // Date.now() is millis since 1970 epoch, we need seconds
        const channelEpoch = 0;
        const chHeader = new common.ChannelHeader({ type: common.HeaderType.CONFIG_UPDATE, version: channelObject.version, timestamp: channelTimestamp, channel_id: channelName, epoch: channelEpoch });

        // Common header
        const header = new common.Header({ channel_header: chHeader.toBuffer() });

        // Form the payload header/data
        const payload = new common.Payload({ header: header, data: configUpdateEnv.toBuffer() });

        // Form and return the envelope
        const envelope = new common.Envelope({ payload: payload.toBuffer() });
        return envelope;
    }

const configUpdate = new common.ConfigUpdate({ channel_id: channelName, read_set: readSet, write_set: writeSet});
    const configUpdateEnv= new common.ConfigUpdateEnvelope({ config_update: configUpdate.toBuffer(), signatures: [] });

    // Channel header
    const channelTimestamp = new google.protobuf.Timestamp({ seconds: Date.now()/1000, nanos: 0 }); // Date.now() is millis since 1970 epoch, we need seconds
    const channelEpoch = 0;
    const chHeader = new common.ChannelHeader({ type: common.HeaderType.CONFIG_UPDATE, version: channelVersion, timestamp: channelTimestamp, channel_id: channelName, epoch: channelEpoch });

    // Common header
    const header = new common.Header({ channel_header: chHeader.toBuffer() });

    // Form the payload header/data
    const payload = new common.Payload({ header: header, data: configUpdateEnv.toBuffer() });

    // Form and return the envelope
    const envelope = new common.Envelope({ payload: payload.toBuffer() });
    return envelope;
}