Handle client serialization

Author: robgridley

src/Client.php

@@ -52,6 +52,16 @@ public function __construct(SoapFactory $soapFactory, $host, $login, $password,
         $this->url = sprintf('%s://%s/rpc/services/', $scheme, $host);
     }
 
+    /**
+     * Prepare the instance for serialization.
+     *
+     * @return string[]
+     */
+    public function __sleep()
+    {
+        return ['soapFactory', 'url'];
+    }
+
     /**
      * Dynamically retrieve the specified model.
      *