diff --git a/dio/lib/src/adapters/io_adapter.dart b/dio/lib/src/adapters/io_adapter.dart
index c22dc08aa..45c270459 100644
--- a/dio/lib/src/adapters/io_adapter.dart
+++ b/dio/lib/src/adapters/io_adapter.dart
@@ -199,7 +199,7 @@ class IOHttpClientAdapter implements HttpClientAdapter {
 
   @override
   void close({bool force = false}) {
-    _closed = _closed;
+    _closed = true;
     _defaultHttpClient?.close(force: force);
   }
 }