<tbody>
    <tr>
    <th>queue</th>
    <td><code class="type">Dispatch​Queue</code></td></td>
    <td><p>dispatch queue to start the chain on</p>
</td>
</tr>
<tr>
    <th>handler</th>
    <td><code class="type">@escaping () throws -&gt; Promise&lt;A&gt;</code></td></td>
    <td><p>handler to run</p>
</td>
</tr>
  </tbody>
</table>
  <h4>Returns</h4>
  <p>Promise</p>

<html><body><pre class="highlight"><code><span class="keyword">public</span> <span class="keyword">func</span> <span class="function">`try`