#include <QCoreApplication>

#include <QTcpSocket>

#include <windows.h>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    QTcpSocket tcpSocket;

    const auto writeToSocket = [&](){
        const auto written = tcpSocket.write(QByteArray(8192, '1'));
        qDebug() << "Sending " << written << " bytes";
    };

    QObject::connect(&tcpSocket, &QAbstractSocket::connected, &tcpSocket, [&](){
        int sndVal = 0;
        int sndLen = sizeof(int);
        getsockopt( tcpSocket.socketDescriptor(), SOL_SOCKET, SO_SNDBUF, (char*)&sndVal, &sndLen);

        int rcvVal = 0;
        int rcvLen = sizeof(int);
        getsockopt( tcpSocket.socketDescriptor(), SOL_SOCKET, SO_RCVBUF, (char*)&rcvVal, &rcvLen);

        qDebug() << "Client connected!" << " sndVal = " << sndVal << " recvVal = " << rcvVal;
        writeToSocket();
    });
    QObject::connect(&tcpSocket, &QIODevice::bytesWritten,
                     &tcpSocket, [&](auto bytes){
        qDebug() << "Bytes written = " << bytes;
        writeToSocket();
    });
    QObject::connect(&tcpSocket, &QAbstractSocket::errorOccurred,
                     &tcpSocket, [](auto error){
        qDebug() << "Error " << error;
    });

    tcpSocket.connectToHost(QHostAddress::LocalHost, 55666);

    return a.exec();
}