code: @NotNull
      public static OptionalInt ofNullable(@Nullable Integer value) {
          return value == null ? EMPTY : new OptionalInt(value);
      }
docs: Returns an {@code OptionalInt} with the specified value, or empty {@code OptionalInt} if value is null.
  
  @param value the value which can be null
  @return an {@code OptionalInt}
  @since 1.2.1