/th>
</tr></thead>
<tbody>
<tr>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">B</span><span class="special">::</span><span class="identifier">value_type</span></code>
                </p>
              </td>
<td>
              </td>
<td>
                <p>
                  The return type of the <code class="computeroutput"><span class="identifier">message</span><span class="special">::</span><span class="identifier">body</span></code>
                  m