code: public static Offset<Integer> offset(Integer value) {
      checkNotNull(value);
      if (value.intValue() < 0) {
        throw valueNotPositive();
      }
      return new Offset<Integer>(value);
    }
docs: Creates a new {@link Offset}.
  
  @param value the value of the offset.
  @return the created {@code Offset}.
  @throws NullPointerException if the given value is {@code null}.
  @throws IllegalArgumentException if the given value is negative.