title: How to get Map object in react-leaflet on zoom change event
body: <p>I am using react-leaflet for showing non-geographical map. 
  I also added some event for zoom changing. (<strong><code>onZoomEnd()</code></strong>)</p>
  
  <p>I wonder how to access map object or map component and get current zoom level. Or other maps props?</p>
  
  <pre><code>  &lt;Map
                  center={this.getCalculatedCenterFromState()}
                  zoom={this.getCalculatedZoomFromState()}
                  minZoom={this.getCalculatedMinZoomFromState()}
                  maxZoom={2}
                  onZoomEnd={this.mapService.handleZoomstart(/* map.object */)}
  
  
                 &gt;
  &lt;/Map
  </code></pre>
  
  <p>I need to access map object in handler method</p>
  
  <pre><code>handleZoomstart = (map) =&gt; {
          // TODO handle move event
      };
  </code></pre>