code: @Reference(policy = DYNAMIC, cardinality = MULTIPLE)
      public void addListener(final PathChangeListener pListener) {
          requireNonNull(pListener, "Observer is null");
          observerInitSwitch.add(pListener);
      }
docs: Whiteboard bind-method for {@link PathChangeListener} services exported by any client bundle. This
  method is called when a client exports a service which implements the {@link PathChangeListener} interface.
  
  @param pListener File observer service to be registered.