code: @Nullable
      public static String getVariantForView(@NonNull View view) {
          for (Map.Entry<String, HashMap<Integer, String>> entry : bindings.entrySet()) {
              if (entry.getValue().containsKey(view.getId())) {
                  return entry.getKey();
              }
          }
          return null;
      }
docs: Returns the variant associated with the view.
  
  @param view a View that is associated to an index through databinding.
  @return the variant name or {@code null} if unspecified.
  @throws IllegalArgumentException if the view is not part of a databinding layout.