Recursive recursiveCoro(string const &directory)
{
    chdir(directory.c_str());               // change to the directory

    while ((entry = nextEntry()))           // visit all its entries
    {
        string const &name = entry.name();
        co_yield name;                      // yield the entry's name

        if (entry.type() == DIRECTORY)      // a directory?
        {                                   // get the full path
            string path = pathName(directory, name);
            co_yield path;                  // yield the full path

            auto rec = recursiveCoro(path); // visit the entries of 
            string next;                    // the subdir (and of its
            while (rec.next(&next))         // subdirs)
                co_yield next;              // and yield them
        }
    }
}
