Added check to Instrumentation mapResult hook to check for presence of …

…@metadata element in the Aws\Result object, as @metadata is not always set for all instrumented functions.

src/Aws/src/AwsSdkInstrumentation.php

@@ -109,9 +109,17 @@ public function activate(): bool
 
             /** @psalm-suppress PossiblyInvalidArgument */
             $end_middleware = Middleware::mapResult(function (ResultInterface $result) {
-                $this->span->setAttributes([
-                    'http.status_code' => $result['@metadata']['statusCode'], //@phan-suppress-current-line PhanTypeMismatchDimFetch
-                ]);
+                /**
+                 * Some AWS SDK Funtions, such as S3Client->getObjectUrl() do not actually perform on the wire comms
+                 * with AWS Servers, and therefore do not return with a populated AWS\Result object with valid @metadata
+                 * Check for the presence of @metadata before extracting status code as these calls are still
+                 * instrumented.
+                 */
+                if (isset($result['@metadata'])) {
+                    $this->span->setAttributes([
+                        'http.status_code' => $result['@metadata']['statusCode'], //@phan-suppress-current-line PhanTypeMismatchDimFetch
+                    ]);
+                }
 
                 $this->span->end();
                 $this->scope->detach();