iOS SDK waitUntilFinished一直阻塞主线程

1. 根据demo、测试用例和文档上的方法运行waitUntilFinished都会长期阻塞主线程
Warning: A long-running operation is being executed on the main thread. Break on warnBlockingOperationOnMainThread() to debug.
        OSSTask * initTask = [client multipartUploadInit:init];
        [initTask waitUntilFinished];

2. 我想问一下，要实现断点续传，是不是只按照文档这部分，是没办法实现的，还需要通过分片上传，这部分代码只是用在分片上传暂停之后，继续续传
__block NSString * uploadId = nil;
OSSInitMultipartUploadRequest * init = [OSSInitMultipartUploadRequest new];
init.bucketName = <bucketName>;
init.objectKey = <objectKey>;
// 以下可选字段的含义参考：
// append.contentType = @"";
// append.contentMd5 = @"";
// append.contentEncoding = @"";
// append.contentDisposition = @"";
// init.objectMeta = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"value1", @"x-oss-meta-name1", nil];
// 先获取到用来标识整个上传事件的UploadId
OSSTask * task = [client multipartUploadInit:init];
[[task continueWithBlock:^id(OSSTask *task) {
    if (!task.error) {
        OSSInitMultipartUploadResult * result = task.result;
        uploadId = result.uploadId;
    } else {
        NSLog(@"init uploadid failed, error: %@", task.error);
    }
    return nil;
}] waitUntilFinished];
// 获得UploadId进行上传，如果任务失败并且可以续传，利用同一个UploadId可以上传同一文件到同一个OSS上的存储对象
OSSResumableUploadRequest * resumableUpload = [OSSResumableUploadRequest new];
resumableUpload.bucketName = <bucketName>;
resumableUpload.objectKey = <objectKey>;
resumableUpload.uploadId = uploadId;
resumableUpload.partSize = 1024 * 1024;
resumableUpload.uploadProgress = ^(int64_t bytesSent, int64_t totalByteSent, int64_t totalBytesExpectedToSend) {
    NSLog(@"%lld, %lld, %lld", bytesSent, totalByteSent, totalBytesExpectedToSend);
};
resumableUpload.uploadingFileURL = [NSURL fileURLWithPath:<your file path>];
OSSTask * resumeTask = [client resumableUpload:resumableUpload];
[resumeTask continueWithBlock:^id(OSSTask *task) {
    if (task.error) {
        NSLog(@"error: %@", task.error);
        if ([task.error.domain isEqualToString:OSSClientErrorDomain] && task.error.code == OSSClientErrorCodeCannotResumeUpload) {
            // 该任务无法续传，需要获取新的uploadId重新上传
        }
    } else {
        NSLog(@"Upload file success");
    }
    return nil;
}];
// [resumeTask waitUntilFinished];
// [resumableUpload cancel];
谢谢