class tcp_connection
{
public:
void start() {
    boost::asio::async_read(socket, boost::asio::buffer(buf), boost::asio::transfer_at_least(1), boost::bind(&tcp_connection::handler, error, bytes_transferred));
}
private:
boost::array<unsigned char, 500000000> buf;
void handler(error, bytes) {
    std::cout << buf.data() << std::endl;

    boost::asio::async_write(socket, response_buffer, boost::bind(&tcp_connection, handler));
}
}