docs: private Service listenTo(Service delegate) {
          delegate.addListener(new Listener() {
              @Override
              public void starting() {
                  // Do nothing
              }
  
              @Override
              public void running() {
                  // Do nothing
              }
  
              @Override
              public void stopping(State from) {
                  // Do nothing
              }
  
              @Override
              public void terminated(State from) {
                  closeLeaderLatch();
              }
  
              @Override
              public void failed(State from, Throwable failure) {
                  closeLeaderLatch();
              }
          }, MoreExecutors.sameThreadExecutor());
          return delegate;
      }