Method do_read

cpp/src/connection_driver_test.cpp:69–77

        connection_driver(name), reads(rd), writes(wr), spinning(0)  {}

    void do_read() {
        mutable_buffer rbuf = read_buffer();
        size_t size = std::min(reads.size(), rbuf.size);
        if (size) {
            copy(reads.begin(), reads.begin()+size, static_cast<char*>(rbuf.data));
            read_done(size);
            reads.erase(reads.begin(), reads.begin()+size);
        }
    }

    void do_write() {
        const_buffer wbuf = write_buffer();