* 겪고 있는 문제 상황을 최대한 자세하게 작성해주세요.

* 문제 해결을 위해 어떤 시도를 해보았는지 구체적으로 함께 알려주세요.

오류를 해결해 주세요..

코드 따라하다가 혹시 누락된게 있는가 싶어, 최종코드를 복붙했는데도, 아래와 같이 뜹니다.

어떤문제가 있는 걸까요?

/C:/_AppUtil/flutter/.pub-cache/hosted/pub.dartlang.org/google_mobile_ads-3.0.0/lib/src/ump/user_messaging_codec.dart:27:19: Error: Type 'WriteBuffer' not found.

void writeValue(WriteBuffer buffer, dynamic value) {

^^^^^^^^^^^

/C:/_AppUtil/flutter/.pub-cache/hosted/pub.dartlang.org/google_mobile_ads-3.0.0/lib/src/ump/user_messaging_codec.dart:45:41: Error: Type 'ReadBuffer' not found.

dynamic readValueOfType(dynamic type, ReadBuffer buffer) {

^^^^^^^^^^

/C:/_AppUtil/flutter/.pub-cache/hosted/pub.dartlang.org/google_mobile_ads-3.0.0/lib/src/ump/user_messaging_codec.dart:27:19: Error: 'WriteBuffer' isn't a type.

void writeValue(WriteBuffer buffer, dynamic value) {

^^^^^^^^^^^

/C:/_AppUtil/flutter/.pub-cache/hosted/pub.dartlang.org/google_mobile_ads-3.0.0/lib/src/ump/user_messaging_codec.dart:45:41: Error: 'ReadBuffer' isn't a type.

dynamic readValueOfType(dynamic type, ReadBuffer buffer) {

^^^^^^^^^^

2

FAILURE: Build failed with an exception.

* Where:

Script 'C:\_AppUtil\flutter\packages\flutter_tools\gradle\flutter.gradle' line: 1156

* What went wrong:

Execution failed for task ':app:compileFlutterBuildDebug'.

> Process 'command 'C:\_AppUtil\flutter\bin\flutter.bat'' finished with non-zero exit value 1

* Try:

> Run with --stacktrace option to get the stack trace.

> Run with --info or --debug option to get more log output.

> Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 17s

Exception: Gradle task assembleDebug failed with exit code 1

Exited (sigterm)