diff --git a/src/Internal/QueuedWritesFile.php b/src/Internal/QueuedWritesFile.php
index ad91e2b..ef9018f 100644
--- a/src/Internal/QueuedWritesFile.php
+++ b/src/Internal/QueuedWritesFile.php
@@ -38,7 +38,10 @@ public function __construct(
         }
 
         $this->queue = new \SplQueue();
-        $this->writable = $this->mode[0] !== 'r';
+        $this->writable = match ($this->mode) {
+            'r', 'rb' => false,
+            default => true,
+        };
         $this->position = $this->mode[0] === 'a' ? $this->size : 0;
     }