 
   func application(
     _ application: UIApplication,
-    performFetchWithCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult
+    performFetchWithCompletionHandler completion: @escaping (UIBackgroundFetchResult
   ) -> Void) {
     var edit = model
     edit.fetch = .progressing(
       Session.Model.FetchAction(
         hash: Date().hashValue,
-        completion: completionHandler
+        completion: completion
       )
     )
     output.on(.next(edit))

  static func ==(
    left: Session.Model.BackgroundTask.State,
    right: Session.Model.BackgroundTask.State
    ) -> Bool {
    switch (left, right) {
    case (.pending, .pending): return true
    case (.progressing(let a), .progressing(let b)): return a == b

}

extension EditOperation: Equatable {
  public static func ==(
    left: EditOperation,
    right: EditOperation
  ) -> Bool {
    switch (left, right) {
    case (.insertion, .insertion): return true
    case (.deletion, .deletion): return true
