OSS大文件分块并发上传抛异常RequestError: ('Connection aborted.', timeout('timed out',))

bucket.upload_part时偶尔会抛出以下异常：

Exception in thread Thread-43:
Traceback (most recent call last):
File "/usr/lib64/python2.6/threading.py", line 532, in bootstrap_inner
self.run()
File "/usr/lib64/python2.6/threading.py", line 484, in run
self.target(self.__args, *self.__kwargs)
File "ali_concurrence.py", line 43, in do_upload
result = self.bucket.upload_part(self.key, self.upload_id, self.part_number, SizedFileAdapter(self.fileobj, self.num_to_upload))
File "/usr/lib/python2.6/site-packages/oss2-2.1.1-py2.6.egg/oss2/api.py", line 589, in upload_part
data=data)
File "/usr/lib/python2.6/site-packages/oss2-2.1.1-py2.6.egg/oss2/api.py", line 863, in __do_object
return self._do(method, self.bucket_name, key, **kwargs)
File "/usr/lib/python2.6/site-packages/oss2-2.1.1-py2.6.egg/oss2/api.py", line 146, in _do
resp = self.session.do_request(req, timeout=self.timeout)
File "/usr/lib/python2.6/site-packages/oss2-2.1.1-py2.6.egg/oss2/http.py", line 44, in do_request
raise RequestError(e)
RequestError: {'status': -2, 'details': "RequestError: ('Connection aborted.', timeout('timed out',))"}