Dart “正在尝试将挂起的异步计数减少到零以下。”角度省出错

由于我在angularDart v1，我得到了这个错误

正在尝试将挂起的异步计数减少到零以下

如果有人能帮我的话，我真的不知道它是从哪里来的

我真的无法通过密码，因为它太重了，而且有点私密性。我希望有人能帮助我

STACKTRACE:
#0      PendingAsync.increaseCount (package:angular/core/pending_async.dart:48:7)
#1      PendingAsync.decreaseCount (package:angular/core/pending_async.dart:59:54)
#2      RootScope.RootScope.<anonymous closure> (package:angular/core/scope.dart:769:34)
#3      _rootRun (dart:async/zone.dart:892)
#4      _ZoneDelegate.run (dart:async/zone.dart:499)
#5      VmTurnZone._finishTurn (package:angular/core/zone.dart:168:21)
#6      VmTurnZone._onRunBase (package:angular/core/zone.dart:111:43)
#7      _onRunUnary (package:angular/core/zone.dart:122:17)
#8      _CustomZone.runUnary (dart:async/zone.dart:801)
#9      _CustomZone.runUnaryGuarded (dart:async/zone.dart:709)
#10     _CustomZone.bindUnaryCallback.<anonymous closure> (dart:async/zone.dart:735)