code: public static <T1 extends Serializable, T2 extends Serializable> Pair<T1, T2> next(T1 a, T2 b) {
      return new Pair<>(a, b);
    }
docs: <p>next.</p>
  
  @param a a T1 object.
  @param b a T2 object.
  @param <T1> a T1 object.
  @param <T2> a T2 object.
  @return a {@link org.rapidpm.frp.model.serial.Pair} object.