diff --git a/src/HttpMiddleware/HttpMetricsMiddleware.php b/src/HttpMiddleware/HttpMetricsMiddleware.php
index 3e6c9ce..92271f6 100644
--- a/src/HttpMiddleware/HttpMetricsMiddleware.php
+++ b/src/HttpMiddleware/HttpMetricsMiddleware.php
@@ -10,8 +10,6 @@
 
 class HttpMetricsMiddleware
 {
-    protected int|float $duration;
-
     public function __construct(
         private readonly LatencyProfiler $latencyProfiler
     ) {