中国区需要转发网络请求。
settings.json 里这么配置，重启vscode生效

"http.proxy":"http://<ip>:<port>","remote.extensionKind":{"Gitihub.copilot":["ui"],"Gitihub.copilot-chat":["ui"],"Gitihub.copilot-labs":["ui"],"Gitihub.copilot-chat-labs":["ui"],"pub.name":["ui"]}