Simplified client logic by removing header based api call and add las…

…tRequestHeaders method.

src/BaseClient.php

@@ -47,6 +47,8 @@ class BaseClient
     /** @var ?callable */
     private $accessTokenExpiredCallback = null;
 
+    private $lastRequestHeaders = null;
+
     /**
      * BaseClient constructor.
      */
@@ -376,9 +378,7 @@ public function request(string $method, string $url, array $options, array $resp
             }
         }
 
-        if ($method === 'HEAD' && $response->getStatusCode() === 200) {
-            return $response->getHeaders();
-        }
+        $this->lastRequestHeaders = $response->getHeaders();
 
         return $this->decodeResponse($response, $responseTypes, $url);
     }

src/Client.php

@@ -1800,31 +1800,6 @@ public function getShippingLabel(string $shippingLabelId): ?string
         return $this->request('GET', $url, $options, $responseTypes);
     }
 
-    /**
-     * Retrieves the headers of a shipping label by shipping label id. Shipping label metadata, for example the X-Track-And-Trace-Code, are added as headers
-     * in the response.
-     *
-     * @param string $shippingLabelId
-     * @return string|null
-     * @throws Exception\ConnectException
-     * @throws Exception\Exception
-     * @throws Exception\RateLimitException
-     * @throws Exception\ResponseException
-     * @throws Exception\UnauthorizedException
-     */
-    public function getShippingLabelHeaders(string $shippingLabelId): ?array
-    {
-        $url = "retailer/shipping-labels/{$shippingLabelId}";
-        $options = [
-            'produces' => 'application/vnd.retailer.v10+pdf',
-        ];
-        $responseTypes = [
-            '404' => 'null',
-        ];
-
-        return $this->request('HEAD', $url, $options, $responseTypes);
-    }
-
     /**
      * Retrieves all event notification subscriptions for a given retailer. Each subscription may have different types
      * of events and a destination, which could either be a URL (for WEBHOOK) or a topic name (for GCP_PUBSUB).