Fix FailureEnvelope metadata calculation

Author: viktorprogger

phpbench.json

@@ -2,7 +2,7 @@
     "$schema":"./vendor/phpbench/phpbench/phpbench.schema.json",
     "runner.bootstrap": "vendor/autoload.php",
     "runner.path": "tests/Benchmark",
-    "runner.revs": 100000,
+    "runner.revs": 10000,
     "runner.iterations": 5,
     "runner.warmup": 5
 }

src/Middleware/FailureHandling/FailureEnvelope.php

@@ -10,7 +10,9 @@
 
 final class FailureEnvelope implements EnvelopeInterface
 {
-    use EnvelopeTrait;
+    use EnvelopeTrait {
+        getMetadata as getMetadataParent;
+    }
 
     public const FAILURE_META_KEY = 'failure-meta';
 
@@ -28,7 +30,7 @@ public static function fromMessage(MessageInterface $message): self
 
     public function getMetadata(): array
     {
-        $meta = $this->message->getMetadata();
+        $meta = $this->getMetadataParent();
         $meta[self::FAILURE_META_KEY] = array_merge($meta[self::FAILURE_META_KEY] ?? [], $this->meta);
 
         return $meta;