pan="2" align="center" valign="top" width="25"><img alt="[Important]" src="../../../../../../doc/src/images/important.png"></td>
<th align="left">Important</th>
</tr>
<tr><td align="left" valign="top"><p>
          Using <span class="emphasis"><em>protected_fixedsize_stack</em></span> is expensive. That
          is, launching a new coroutine with a new stack is expensive; the allocated
          stack is just as efficient to use as any other stack.
        </p></td></tr>
</table></div>
<div class="note"><t