当我开始运行appium flutter脚本时，出现此错误并等待5分钟。之后，它将继续执行。

[FlutterDriver] Attempt #1
[FlutterDriver] Connecting to Dart Observatory: ws://127.0.0.1:39420/uVLSKORHloI=/ws
[FlutterDriver] Connected to ws://127.0.0.1:39420/uVLSKORHloI=/ws
[FlutterDriver] "ext.flutter.driver" is not found in "extensionRPCs" ["ext.ui.window.scheduleFrame"]
[FlutterDriver] Cannot get Dart Isolate
[FlutterDriver] Error: "ext.flutter.driver" is not found in "extensionRPCs" ["ext.ui.window.scheduleFrame"]
[FlutterDriver]     at Object.wrappedLogger.errorAndThrow (/usr/local/lib/node_modules/appium-flutter-driver/node_modules/appium-support/lib/logging.js:74:35)
[FlutterDriver]     at Client.onOpenListener (/usr/local/lib/node_modules/appium-flutter-driver/lib/sessions/observatory.ts:91:17)
[FlutterDriver]     at runmicrotasks (<anonymous>)
[FlutterDriver]     at processTicksAndRejections (internal/process/task_queues.js:93:5)
[FlutterDriver] Waiting 300 seconds before trying...
(node:71547) UnhandledPromiseRejectionWarning: Error: "ext.flutter.driver" is not found in "extensionRPCs" ["ext.ui.window.scheduleFrame"]
    at Object.wrappedLogger.errorAndThrow (/usr/local/lib/node_modules/appium-flutter-driver/node_modules/appium-support/lib/logging.js:74:35)
    at Client.onOpenListener (/usr/local/lib/node_modules/appium-flutter-driver/lib/sessions/observatory.ts:91:17)
    at runmicrotasks (<anonymous>)
    at processTicksAndRejections (internal/process/task_queues.js:93:5)
(node:71547) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block,or by rejecting a promise which was not handled with .catch(). (rejection id: 3)

问题在哪里？