如何知道从哪一点触发HttpClient任务取消

public async Task<HttpResponseMessage> SendHttpRequest()
{
    HttpResponseMessage response = null;
    try
    {
        HttpClient client = new HttpClient();
        string accessToken = await GetBearerToken(resourceUrl, clientId, clientSecret, tokenProviderUrl);
        if (!string.IsNullOrEmpty(accessToken))
            httpRequest.Headers.Add("Authorization", ("Bearer " + accessToken));

        response = await client.SendAsync(httpRequest);
    }
    catch(Exception ex)
    {
        log.Error("Exception raised while sending HTTP request");
        log.Error("Exception details : " + ex.Message);
    }           

    return response;
}

public async Task<string> GetBearerToken()
{           
    HttpResponseMessage response = null;
    HttpClient client = new HttpClient();
    string token = "";
    try
    {
        var request = new HttpRequestMessage(HttpMethod.Post, tokenProviderUrl);
        request.Content = new FormUrlEncodedContent(new Dictionary<string, string> {
            { "client_id",clientId},
            { "client_secret", clientSecret },
            { "grant_type", "client_credentials" },
            { "resource", resource },
        });

        response = await client.SendAsync(request);                
        var payload = JObject.Parse(await response.Content.ReadAsStringAsync());
        token = payload.Value<string>("access_token");                
    }
    catch (HttpRequestException ex)
    {
        log.Error("Error in GetToken : " + ex.Message.ToString());
    }
    return token;
}

我在这里面临的问题是,有时,这段代码会抛出一个异常,说“Task was cancelled”(任务被取消了),但不是每次都这样。我在网上搜索过 this

奇怪的是,任务等待30分钟(或者我们指定的任何超时),然后抛出task was cancelled异常,这让我抓狂。

我想知道为什么当我们不明确地重新请求任务时,任务会被取消,任务会从谁或哪里被取消?有没有办法找到取消申请的来源?

请假设所有变量都有正确的值,尽管这里没有提到。

异常消息:

任务已取消。

这是异常堆栈跟踪:

异常堆栈跟踪:位于 任务)在 System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(任务 任务)在 System.Net.Http.HttpClient.dúu58.MoveNext() ---从引发异常的上一个位置的堆栈结束跟踪-- 任务)在 System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(任务 在System.Runtime.CompilerServices.TaskAwaiter`1.GetResult() 在SampleProject.dúu 2.MoveNext()中 ---从引发异常的上一个位置的堆栈结束跟踪---