.cpp

void Server::sendTextToOne(QString text,ClientThread* target){
    QByteArray block;
    QDataStream out(&block,QIODevice::WriteOnly);
    out.setVersion(QDataStream::Qt_5_8);

    out << (quint32)0 << text;

    out.device()->seek(0);
    out << (quint32)(block.size() - sizeof(quint32));
    qDebug() << "block.size() = " << block.size();

    qint64 x = 0;
    while(x < block.size()){
        qint64 y = target->getTcpSocket()->write(block);
        x+=y;
        qDebug() << target->getUsername()<< " /sent " << x ;
        qDebug() << "-----";
    }
}