uffer sizes.
            </li>
<li class="listitem">
              The completion_condition function object returns 0.
            </li>
</ul></div>
<p>
          This operation is implemented in terms of zero or more calls to the stream's
          async_write_some function, and is known as a <span class="bold"><strong>composed
          operation</strong></span>. The program must ensure that the stream performs
          no other write operations (such as async_write, the stream's async_write_some
       