Revert "Remove unnecessary import (#175)" (#177)
This reverts commit b386f6c68f9f6c7c457bab4954589bdecd0c968e.
Reverting to publish with exactly the same `lib/` content as the
previous publish.
diff --git a/lib/src/empty_unmodifiable_set.dart b/lib/src/empty_unmodifiable_set.dart
index 882b6c8..44bd5ef 100644
--- a/lib/src/empty_unmodifiable_set.dart
+++ b/lib/src/empty_unmodifiable_set.dart
@@ -6,6 +6,8 @@
import 'package:collection/collection.dart';
+import 'unmodifiable_wrappers.dart';
+
/// An unmodifiable, empty set which can be constant.
class EmptyUnmodifiableSet<E> extends IterableBase<E>
with UnmodifiableSetMixin<E>
