code: public SimplePageable<T> with(int pageSize) {
  
      Assert.isTrue(pageSize > 0, "Page size [%d] must be greater than 0", pageSize);
  
      this.pageSize = pageSize;
  
      return this;
    }
docs: Sets the size used by this {@link Pageable} for dividing elements into {@link Page Pages} using the given value.
  
  @param pageSize integer indicating the number of elements per {@link Page}.
  @return this {@link SimplePageable}.
  @throws IllegalArgumentException if {@code pageSize} is less than equal to {@literal 0}.