</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">body</span><span class="special">);</span>

    <span class="comment">/** Initialize the writer.

        This is called after construction and before the first
        call to `get`. The message is valid and complete upon
        entry.

        @param ec Set to the error, if any occurred.
    */</span>
    <span class="keyword">void</span>
    <span class="identifier">init</span><span class="special">(</s