Add description to the getRetryListener method

Author: Hectorhammett

BigQuery/src/Connection/Rest.php

@@ -437,6 +437,13 @@ private function getRequestWrapper(array $config): RequestWrapper
         return new RequestWrapper($config);
     }
 
+    /**
+     * Returns a function that the RequestWrapper uses between retries. In our listener we modify the call options
+     * to add the `retryAttempt` field to the call options for our Auth httpHandler logging logic. This way, the logging
+     * logic has access to the retry attempt.
+     *
+     * @return callable
+     */
     private function getRetryListener(): callable
     {
         return function (Exception $ex, int $retryAttempt, array &$arguments) {

BigQuery/tests/Unit/BigQueryClientTest.php

@@ -774,13 +774,13 @@ public function testRetryLogging()
             new Response(200, [], json_encode(['access_token' => 'token']))
         ]);
 
-        $retryHeaderAppeared = false;
+        $retryCallOptionAppeared = false;
         $logger = $this->prophesize(LoggerInterface::class);
         $logger->debug(
-            Argument::that(function (string $jsonString) use (&$retryHeaderAppeared) {
+            Argument::that(function (string $jsonString) use (&$retryCallOptionAppeared) {
                 $jsonParsed = json_decode($jsonString, true);
                 if (isset($jsonParsed['jsonPayload']['retryAttempt'])) {
-                    $retryHeaderAppeared = true;
+                    $retryCallOptionAppeared = true;
                 }
                 return true;
             })
@@ -809,6 +809,6 @@ public function testRetryLogging()
         );
 
         $client->startQuery($queryConfig);
-        $this->assertTrue($retryHeaderAppeared);
+        $this->assertTrue($retryCallOptionAppeared);
     }
 }