copyWith method Null safety

ZipItem<I1, I2> copyWith(
  1. {I1? item1,
  2. I2? item2}
)

Implementation

ZipItem<I1, I2> copyWith({
  I1? item1,
  I2? item2,
})
    // currently broken because references are passed as deep copies
    =>
    ZipItem(
      item1 ?? this.item1,
      item2 ?? this.item2,
    );