title: React native maps draggable marker onDragEnd position?
body: <p>I just started using react native maps~0.22.1, and I am having trouble acquiring the draggable marker onDragend new position;
  I followed the documentation even though it is a bit vag, but the result is undefined;</p>
  
  <p>Here is my code:</p>
  
  <pre><code>&lt;Marker
          ref={(ref) =&gt; { this.marker = ref; }}
          draggable
          onDragEnd={(t, map, coords) =&gt; this.setDestination(coords)}
          coordinate={destination}
          position={destination}
          centerOffset={{ x: -18, y: -60 }}
          anchor={{ x: 0.69, y: 1 }}
          pinColor={COLOR.marker}
          onDragStart={() =&gt; this.setMarkerPosition()}
        /&gt;
  </code></pre>
  
  <p>setDestination function:</p>
  
  <pre><code>setDestination(coords) {
      const { destination } = this.props;
      const lat = coords.lat();
      const long = coords.lng();
      console.log('seperate:', lat, long);
      console.log('destina:', coords);
      this.props
        .dispatch($setDestination(coords.lat(), coords.lng()))
        .catch((error) =&gt; this.props.dispatch(Activity.$toast('failure', error.message)));
  
      this.setState((prevState) =&gt; ({
        isVisible: !prevState.isVisible,
        destination: destination[0].fullAddress,
      }));
    }
  </code></pre>