title: Auto open markers popup on react-leaflet map
body: <p>I use some markers on react-leaflet map to show various text.<br>
  But I can not find a flag for the autoOpen tooltip.</p>
  
  <p>I get (position, children, onOpen, onClose) as available attributes.</p>
  
  <pre><code>render() {
      return (
          &lt;div className={'ShapeLayer'}&gt;
              {
                  this.shapes.map(shape =&gt; {
                      return (
                          &lt;Marker key={shape['id']} position={shape['coordinates']} draggable={false} opacity={1}&gt;
                              &lt;Popup&gt;
                                  &lt;span&gt;{shape['text']}&lt;/span&gt;
                              &lt;/Popup&gt;
                          &lt;/Marker&gt;
                      );
  
                  })
              }
          &lt;/div&gt;
      )
  }
  </code></pre>
  
  <p>This is done with this code on native leaflet</p>
  
  <pre><code>var marker = L.marker(shapess[i]['coordinates'], {
          opacity: 0.01
      }).bindTooltip(shapess[i]['text'],
          {
              permanent: true,
              className: "shapesText" + i,
              offset: [0, 0],
              direction: "center"
          }
      ).openTooltip().addTo(mymap);
  </code></pre>
  
  <p>How can I do the same on react_leflet</p>