use maps.Clone() in Go 1.21+

Author: mai7star

helper.go

@@ -0,0 +1,11 @@
+//go:build !go1.21
+
+package mapset
+
+func mapclone[T comparable](m map[T]struct{}) map[T]struct{} {
+	c := make(map[T]struct{}, len(m))
+	for k := range m {
+		c[k] = struct{}{}
+	}
+	return c
+}

helper_1_21.go

@@ -0,0 +1,9 @@
+//go:build go1.21
+
+package mapset
+
+import "maps"
+
+func mapclone[T comparable](m map[T]struct{}) map[T]struct{} {
+	return maps.Clone(m)
+}

threadunsafe.go

@@ -82,11 +82,8 @@ func (s *threadUnsafeSet[T]) Clear() {
 }
 
 func (s *threadUnsafeSet[T]) Clone() Set[T] {
-	clonedSet := newThreadUnsafeSetWithSize[T](s.Cardinality())
-	for elem := range *s {
-		clonedSet.add(elem)
-	}
-	return clonedSet
+	t := threadUnsafeSet[T](mapclone(*s))
+	return &t
 }
 
 func (s *threadUnsafeSet[T]) Contains(v ...T) bool {