我目前正在开发一个iOS应用程序，我必须在认证过程后在Box上上传多个图像。当我一次选择5个以上的图像时，它总是上传5个图像，超过5个图像停止上传。错误消息出现在日志中，如::
[BoxAPIOperation connectionDidFinishLoading:]: BoxAPIOperation <BoxAPIMultipartToJSONOperation: 0xa64eb20> POST https://upload.box.com/api/2.1/files/content did finsh loading
2014-08-25 12:53:36.484 Pbm[13499:4903] -[BoxAPIOperation finish]: BoxAPIOperation <BoxAPIMultipartToJSONOperation: 0xa64eb20> POST https://upload.box.com/api/2.1/files/content finished with state 3
2014-08-25 12:53:36.485 Pbm[13499:4903] -[BoxAPIOperation connection:didFailWithError:]: BoxAPIOperation <BoxAPIMultipartToJSONOperation: 0xa642d00> POST https://upload.box.com/api/2.1/files/content did fail with error Error Domain=NSURLErrorDomain Code=-1021 "request body stream exhausted" UserInfo=0xa334970 {NSErrorFailingURLStringKey=https://upload.box.com/api/2.1/files/content, NSErrorFailingURLKey=https://upload.box.com/api/2.1/files/content, NSLocalizedDescription=request body stream exhausted, NSUnderlyingError=0xa32fb70 "request body stream exhausted"}
2014-08-25 12:53:36.485 Pbm[13499:4903] response : (null)
2014-08-25 12:53:36.485 Pbm[13499:4903] error : Error Domain=NSURLErrorDomain Code=-1021 "request body stream exhausted" UserInfo=0xa334970 {NSErrorFailingURLStringKey=https://upload.box.com/api/2.1/files/content, NSErrorFailingURLKey=https://upload.box.com/api/2.1/files/content, NSLocalizedDescription=request body stream exhausted, NSUnderlyingError=0xa32fb70 "request body stream exhausted"}
我没有得到“请求正文流耗尽”的问题。如果有人在Box上完成了上传过程，请帮帮我。
提前致谢。