C# 创建pull请求并以编程方式向其添加审阅者、工作项

我使用以下语句创建了一个请求：

pullRequest = gitClient.CreatePullRequestAsync(gitPullRequest, shrdRepo.Id, 
                         supportsIterations: true, cancellationToken: token).Result;

我正在尝试向其中添加审阅者和工作项。 对于审阅者添加，尝试使用以下语句标识审阅者。但我有个例外：

IdentityHttpClient identityHttpClient = new IdentityHttpClient(new Uri(c_collectionUri), creds);
IdentitiesCollection identitiesPerAlias = identityHttpClient.ReadIdentitiesAsync(IdentitySearchFilter.MailAddress, mail, cancellationToken:token).Result;

例外情况是：

Exception when looking for vsts identity for alias xyzxyz.com. System.AggregateException: One or more errors occurred. ---> Microsoft.VisualStudio.Services.WebApi.VssResourceNotFoundException: API resource location 28010c54-d0c0-4c89-a5b0-1c9e188b9fb7 is not registered on https://dev.azure.com/xyz.
   at Microsoft.VisualStudio.Services.WebApi.VssHttpClientBase.<CreateRequestMessageAsync>d__34.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.Services.WebApi.VssHttpClientBase.<SendAsync>d__28`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.Services.Identity.Client.IdentityHttpClient.<ReadIdentitiesAsyncInternal>d__42.MoveNext()
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
   at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification)
   at System.Threading.Tasks.Task`1.get_Result()
   at AzureDevOpsSample.Program.<SearchForReviewerVstsIdentity>d__4.MoveNext() in D:\Projects\tools_release_notes\tools-ReleaseNotes_PR_Working\createPrForSharedRepo\Program.cs:line 349
---> (Inner Exception #0) Microsoft.VisualStudio.Services.WebApi.VssResourceNotFoundException: API resource location 28010c54-d0c0-4c89-a5b0-1c9e188b9fb7 is not registered on https://dev.azure.com/xyz.
   at Microsoft.VisualStudio.Services.WebApi.VssHttpClientBase.<CreateRequestMessageAsync>d__34.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.Services.WebApi.VssHttpClientBase.<SendAsync>d__28`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.Services.Identity.Client.IdentityHttpClient.<ReadIdentitiesAsyncInternal>d__42.MoveNext()<---

查找别名xyzxyz.com的vsts标识时出现异常。System.AggregateException:发生一个或多个错误。-->Microsoft.VisualStudio.Services.WebApi.VssResourceNotFoundException:API资源位置28010c54-d0c0-4c89-a5b0-1c9e188b9fb7未在上注册https://dev.azure.com/xyz. 位于Microsoft.VisualStudio.Services.WebApi.VssHttpClientBase.d_u34.MoveNext（）上 ---来自引发异常的上一个位置的堆栈结束跟踪--- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务） 在System.Runtime.CompilerServices.TaskWaiter.HandleNonSuccessAndDebuggerNotification（任务任务）中 位于Microsoft.VisualStudio.Services.WebApi.VssHttpClientBase.d_u28`1.MoveNext（） ---来自引发异常的上一个位置的堆栈结束跟踪--- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务） 在System.Runtime.CompilerServices.TaskWaiter.HandleNonSuccessAndDebuggerNotification（任务任务）中 在Microsoft.VisualStudio.Services.Identity.Client.IdentityHttpClient.d_u42.MoveNext（）上 ---内部异常堆栈跟踪的结束--- 位于System.Threading.Tasks.Task.ThrowifeException（布尔值IncludeTaskCanceledException） 位于System.Threading.Tasks.Task`1.GetResultCore（布尔waitCompletionNotification） 在System.Threading.Tasks.Task`1.get_Result（）中 在d:\Projects\tools\u release\u notes\tools-ReleaseNotes\u PR\u Working\createPrForSharedRepo\Program.cs中的AzureDevSample.Program.d\u 4.MoveNext（）中：第349行 --->（内部异常#0）Microsoft.VisualStudio.Services.WebApi.VssResourceNotFoundException:API资源位置28010c54-d0c0-4c89-a5b0-1c9e188b9fb7未在上注册https://dev.azure.com/xyz. 位于Microsoft.VisualStudio.Services.WebApi.VssHttpClientBase.d_u34.MoveNext（）上 ---来自引发异常的上一个位置的堆栈结束跟踪--- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务） 在System.Runtime.CompilerServices.TaskWaiter.HandleNonSuccessAndDebuggerNotification（任务任务）中 位于Microsoft.VisualStudio.Services.WebApi.VssHttpClientBase.d_u28`1.MoveNext（） ---来自引发异常的上一个位置的堆栈结束跟踪--- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务） 在System.Runtime.CompilerServices.TaskWaiter.HandleNonSuccessAndDebuggerNotification（任务任务）中 在Microsoft.VisualStudio.Services.Identity.Client.IdentityHttpClient.d_u42.MoveNext（）上