pan class="identifier">message</span></code></a> class. It controls both
        the type of the data member of the resulting message object, and the algorithms
        used during parsing and serialization.
      </p>
<h5>
<a name="beast.concepts.Body.h0"></a>
        <span class="phrase"><a name="beast.concepts.Body.associated_types"></a></span><a class="link" href="Body.html#beast.concepts.Body.associated_types">Associated
        Types</a>
      </h5>
<div class="itemizedlist"><ul class="itemizedlist" s