port is required!
  template&lt;typename Archiver&gt;
  void serialize(Archiver&amp; ar, const unsigned int /*version*/) {
    ar &amp; name &amp; lanes &amp; miles_per_hour &amp; length;
  }
};
</pre>
<p>To create a distributed graph for a road map, we supply <tt class="docutils literal"><span class="pre">City</span></tt> and
<tt class="docutils literal"><span class="pre">Highway</span></tt> as the fourth and fifth parameters to <tt class="docutils literal"><span class="pre">adjacency_list</span></tt>,
res