     public func listAll() -> Future<StorageListResult, Error> {
       Future<StorageListResult, Error> { promise in
         self.listAll { result in
-          switch result {
-          case let .success(list):
-            promise(.success(list))
-          case let .failure(error):
-            promise(.failure(error))
-          }
+          promise(result)
         }
       }
     }

    public func downloadURL() -> Future<URL, Error> {
      Future<URL, Error> { promise in
        self.downloadURL { result in
          switch result {
          case let .success(url):
            promise(.success(url))
          case let .failure(error):
            promise(.failure(error))
          }
        }
      }
    }

    public func getMetadata() -> Future<StorageMetadata, Error> {
      Future<StorageMetadata, Error> { promise in
        self.getMetadata { result in
          promise(result)
        }
      }
    }
