title: event.persist is not a function - JEST & Enzyme
body: <p>I am using React 16.3 with JEST and Enzyme as my test utilities, I have an input where when user enters the email and blur the field, a function (handleInputBlur) gets called. In that function I am updating the state (setState) and <code>setState()</code> callback, I am calling another function and pass the event that was passed to <code>handleInputBlur</code> initially.</p>
  
  <p>Now as I understand, since <code>setState</code> is async React does not allow to pass the event in callback of setState. so, I added <code>event.persist()</code> to persist the event. Everything works well so far. </p>
  
  <p>When I try to run the JEST test case that I have written and simulate the <code>blur</code> on the input it calles the function but throws the error : </p>
  
  <pre><code>TypeError: e.persist is not a function
  </code></pre>
  
  <p>I am not able understand what exactly is to be done to get around this issue. </p>