QJsonParseError *error = nullptr;
        QJsonDocument documento = QJsonDocument::fromJson(buffer,error);
        if (error)
        {
            ui->pteRegistro->setPlainText("ERROR JSON:"+error->errorString());
            return;
        }
        QJsonObject obj = documento.object();
        QJsonArray arr = obj.value("Personas").toArray(); // arr.size() == 0 ?