title: leaflet layer control events?
body: <p>All, I want to detect user layer selection in order to synchronize my sidebar with the displayed layers.  </p>
  
  <p>But I don't see any layer control events in the API  reference;  How might I tell when such user layer selection has occurred?  </p>
  
  <p>As an alternative, I've looked at the layer load and unload events, but I don't see any identification in what's returned.  Did I miss that somehow?</p>