Dart WhereIterable does not cache

main.dart

void main() {
  final mappedIterable = ['a', 'b', 'c', 'd'].map((ch) {
    print('mapped $ch');
    return ch;
  }).where((ch) {
    return ch != 'a';
  });
  if (mappedIterable.isNotEmpty) {
    print('iterable is non-empty');
    print(mappedIterable.first);
  }
}