code: protected void checkExistingIsSuperstate(State existingState, State newState) {
      checkExistingIsSuperset(existingState.getProperties().entrySet(), newState.getProperties().entrySet());
    }
docs: Compare an existing state and a new {@link State} to ensure that the existing {@link State} contains all entries in the new
  {@link State}, and update {@link #result} accordingly.