如何处理与网络断开连接时引发的AmazonServiceException

我正在使用AWS mobile SDK for Xamarin（），当我使用GetObjectAsync（）方法从我的S3存储桶获取文件时遇到了一个问题。我的代码：

private async Task<string> GetObjectFromAmazonS3(S3Object s3Object, string fileContent, string bucketName)
    {
        AWSCredentials credential = new BasicAWSCredentials(Constants.S3AccessKey, Constants.S3SecretKey);

        _amazonS3Client = new AmazonS3Client(credential, Amazon.RegionEndpoint.EUCentral1);

        _amazonS3Client.ExceptionEvent += ClientExceptionHandler;

        GetObjectRequest getObjectRequest = new GetObjectRequest
        {
            BucketName = bucketName,
            Key = s3Object.Key
        };

        GetObjectResponse getObjectResponse = await _amazonS3Client.GetObjectAsync(getObjectRequest);

        using (Stream responseStream = getObjectResponse.ResponseStream)
        using (StreamReader reader = new StreamReader(responseStream))
        {
            fileContent = reader.ReadToEnd();
        }

        Logger.Log(Logger.Category.Debugging, "Download S3 Objects to the phone", "Get object " + s3Object.Key + " successfully");

        return fileContent;
    }

私有异步任务GetObjectFromAmazonS3（S3Object S3Object，string fileContent，string bucketName）
{
AWSCredentials Credentials=新的基本凭证（Constants.S3AccessKey，Constants.S3SecretKey）；
_amazonS3Client=新的amazonS3Client（凭证，Amazon.RegionEndpoint.EUCentral1）；
_amazonS3Client.ExceptionEvent+=ClientExceptionHandler；
GetObjectRequest GetObjectRequest=新建GetObjectRequest
{
BucketName=BucketName，
Key=s3Object.Key
};
GetObjectResponse GetObjectResponse=await_amazonS3Client.GetObjectAsync（getObjectRequest）；
使用（Stream responseStream=getObjectResponse.responseStream）
使用（StreamReader=新StreamReader（responseStream））
{
fileContent=reader.ReadToEnd（）；
}
Logger.Log（Logger.Category.debug，“将S3对象下载到手机”，“获取对象”+s3Object.Key+“成功”）；
返回文件内容；
}

问题是，当应用程序等待GetObjectAsync（）方法的响应时，手机与网络断开连接，然后我得到一个异常：

2015-03-03T07:23:27.582Z,Debugging,UnhandledException(Android),Amazon.Runtime.AmazonServiceException: A WebException with status NameResolutionFailure was thrown. 
---> System.Net.WebException: Error: NameResolutionFailure 
==>   at System.Net.HttpWebRequest.EndGetResponse (IAsyncResult asyncResult) [0x00000] in <filename unknown>:0  
==>   at System.Threading.Tasks.TaskFactory`1[System.Net.WebResponse].InnerInvoke (System.Threading.Tasks.TaskCompletionSource`1 tcs, System.Func`2 endMethod, IAsyncResult l) [0x00000] in <filename unknown>:0  
==> --- End of stack trace from previous location where exception was thrown --- 
==>   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x00000] in <filename unknown>:0  ==>   at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1+ConfiguredTaskAwaiter[System.Net.WebResponse].GetResult () [0x00000] in <filename unknown>:0

2015-03-03T07:23:27.582Z，调试，未处理异常（Android），Amazon.Runtime.AmazonServiceException:引发状态为NameResolutionFailure的WebException。
--->System.Net.WebException:错误：NameResolutionFailure
==>在System.Net.HttpWebRequest.EndGetResponse（IAsyncResult asyncResult）[0x00000]中：0
==>在System.Threading.Tasks.TaskFactory`1[System.Net.WebResponse].InnerInvoke（System.Threading.Tasks.TaskCompletionSource`1 tcs，System.Func`2 endMethod，IAsyncResult l）[0x00000]中：0
==>---引发异常的上一个位置的堆栈结束跟踪----
==>在System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw（）[0x00000]中：0==>在System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1+ConfiguredTaskAwaiter[System.Net.WebResponse].GetResult（）[0x00000]中：0

我的应用程序崩溃了。我试图使用ExceptionEvent处理应用程序，但仍然无法捕获此异常

有什么解决这个问题的建议吗？（每次断开wifi连接时，应用程序都会崩溃，这是非常可怕的）