Cast response.headers to dict, because it's not JSON serializable.
Cast response.headers to dict, because
it's not JSON serializable.

Azure/azure-notificationhubs-samples,Azure/azure-notificationhubs-samples,Azure/azure-notificationhubs-samples,Azure/azure-notificationhubs-samples,Azure/azure-notificationhubs-samples,Azure/azure-notificationhubs-samples,Azure/azure-notificationhubs-samples,Azure/azure-notificationhubs-samples,Azure/azure-notificationhubs-samples