Ipad 取消在Google Drive IOS SDK上上载文件

我正在开发使用谷歌硬盘操作文件的IOS应用程序，所以我正在阅读和下载，上传文件每件事都很好，但我找不到如何取消上传文件，因为有时用户需要取消下载或上传，但没有相关文档。谢谢

我找到了如何取消上传，只需执行

[ticket cancelTicket]但我如何从另一个方法访问此票证，她是我的上载方法

- (void)insertFileWithService:(GTLServiceDrive *)service
                    title:(NSString *)title
              description:(NSString *)description
                 parentId:(NSString *)parentId
                 mimeType:(NSString *)mimeType
                     data:(NSData *)data
                fileIndex:(NSIndexPath *)fileIndex
          completionBlock:(void (^)(GTLDriveFile *, NSError *))completionBlock{
GTLDriveFile *file = [GTLDriveFile object];

file.title = title;
file.descriptionProperty = description;
file.mimeType = mimeType;

if (parentId != nil) {
    GTLDriveParentReference *parentRef = [GTLDriveParentReference object];
    parentRef.identifier = parentId; // identifier property of the folder
    file.parents = @[ parentRef ];
    //file.parents = [NSArray arrayWithObjects: parentId, nil];
}

GTLUploadParameters *uploadParameters =
[GTLUploadParameters uploadParametersWithData:data MIMEType:mimeType];
GTLQueryDrive *query =
[GTLQueryDrive queryForFilesInsertWithObject:file
                            uploadParameters:uploadParameters];

GTLServiceTicket *queryTicket =
[service executeQuery:query
    completionHandler:^(GTLServiceTicket *ticket,
                        GTLDriveFile *insertedFile, NSError *error) {


        if (error == nil) {
            completionBlock(insertedFile, nil);

        } else {
            //NSLog(@"An error occurred: %@", error);
            completionBlock(nil, error);
        }
    }];

queryTicket.uploadProgressBlock = ^(GTLServiceTicket *ticket,
                               unsigned long long numberOfBytesRead,
                               unsigned long long dataLength) {
   float myprogress = (1.0 / dataLength * numberOfBytesRead);

   NSLog(@"progress %@ => %f",title,myprogress);
   self.fileManagementViewController.fileTransferProgressTableViewController.progress = myprogress;

};
}

谢谢
我刚刚将所有票证保存在NSmutableArray上，然后使用indexpath取消它们