message: Loaded elements and started transition
diff: package com.navigation.reactnative;
  import android.app.Activity;
  +import android.view.View;
  import java.util.HashSet;
  public class SharedElementTransitioner {
  private Activity activity;
  private HashSet<String> sharedElements;
  + private HashSet<String> loadedSharedElements;
  public SharedElementTransitioner(Activity activity, HashSet<String> sharedElements) {
  this.activity = activity;
  this.sharedElements = sharedElements;
  + this.loadedSharedElements = new HashSet<>();
  + }
  +
  + public void load(String sharedElement) {
  + if (sharedElements.contains(sharedElement) && !loadedSharedElements.contains(sharedElement)) {
  + loadedSharedElements.add(sharedElement);
  + }
  + if(sharedElements.size() == loadedSharedElements.size())
  + activity.startPostponedEnterTransition();
  }
  }
  