title: react-google-maps click the map to get coordinates
body: <p>I'm new to react-google-maps and I want to add an eventlistener to the map such that when I click any point on the map, I can get the coordinate of that point, however, I really don't know where I should add the event Listener. Snippets of my code is as following:</p>
  
  <pre><code>return(
              &lt;GoogleMap
              defaultZoom={10}
              defaultCenter={{ lat: 22.3193, lng: 114.1694 }}
              onClick = {this.homepage} &gt;
              &lt;/GoogleMap&gt;
  );
  </code></pre>
  
  <p>I wonder why it seems that the onClick doesn't work when I click on the map?
  Thank you guys a lot!</p>