title: How can I update marker location in real time when dragging in Google Map v2?
body: <p>When I drag the marker in Google Map, I want to update the marker location in realtime and show it in text up the marker.<br>
  Now I can just update marker location when end the dragging by implement <code>void onMarkerDragEnd(Marker marker)</code>, but can't update the location when I am dragging the marker in map.<br>
  So how can I update or know marker location when I am dragging it in map?</p>