diff --git a/src/HashingStream.php b/src/HashingStream.php
index 6974460..52e9adb 100644
--- a/src/HashingStream.php
+++ b/src/HashingStream.php
@@ -64,9 +64,11 @@ public function read($length): string
             hash_update($this->hashResource, $read);
         }
         if ($this->stream->eof()) {
-            $this->hash = hash_final($this->hashResource, true);
-            if ($this->onComplete) {
-                call_user_func($this->onComplete, $this->hash);
+            if (!$this->hash) {
+                $this->hash = hash_final($this->hashResource, true);
+                if ($this->onComplete) {
+                    call_user_func($this->onComplete, $this->hash);
+                }
             }
         }
 
@@ -93,4 +95,4 @@ private function initializeHash(): void
             $this->key
         );
     }
-}
\ No newline at end of file
+}