n it's possible to write</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="https://docs.oracle.com/javase/8/docs/api/java/lang/IllegalStateException.html?is-external=true" title="class or interface in java.lang">IllegalStateException</a></code> - if one of the following conditions is true
 <ul>
 <li>the associated request is neither upgraded nor the async started
 <li>setWriteListener is called more than once within the scope of the same request.
 </ul></dd>
<dd><code><a href="https: