Add Exists method to Optional

internal/util/util.go

@@ -149,3 +149,8 @@ func (this *Optional[T]) Unset () {
 	this.value = zero
 	this.exists = false
 }
+
+// Exists returns if the value is currently set.
+func (this *Optional[T]) Exists () bool {
+	return this.exists
+}