;</span></code>
            </li>
<li class="listitem">
              <code class="computeroutput"><span class="identifier">value_type</span></code> is <code class="computeroutput"><span class="identifier">State</span></code>
            </li>
<li class="listitem">
              <code class="computeroutput"><span class="identifier">reference_type</span></code> is
              <code class="computeroutput"><span class="identifier">State</span> <span class="keyword">const</span><span class="special">&amp;</sp