code: @NotNull
      public OptionalInt findLast() {
          return reduce(new IntBinaryOperator() {
              @Override
              public int applyAsInt(int left, int right) {
                  return right;
              }
          });
      }
docs: Returns the last element wrapped by {@code OptionalInt} class.
  If stream is empty, returns {@code OptionalInt.empty()}.
  
  <p>This is a short-circuiting terminal operation.
  
  @return an {@code OptionalInt} with the last element
  or {@code OptionalInt.empty()} if the stream is empty
  @since 1.1.8