title: Is it possible to override locale of one specific intl.formatMessage?
body: <p>I use <code>react-intl</code> with <code>en</code> and <code>fr</code>, and my React app is wrapped in </p>
  
  <pre><code>&lt;IntlProvider locale={lang}&gt;
  </code></pre>
  
  <p>so that e.g. when <code>lang</code> is <code>en</code>, all <code>intl.formatMessage</code> calls result in English texts.</p>
  
  <p>What I want to achieve is that I want <code>&lt;IntlProvider locale="en"&gt;</code>, but inside the app, I need one specific <code>intl.formatMessage</code> to be translated into <code>fr</code>.</p>