为什么NSURLSession操作队列在创建和恢复NSURLSessionTask之后是空的?NSURLSessionUploadTask *uploadTask = [self.session uploadTaskWithStreamedRequest:request];// this prints "0"
typedef struct sp_session sp_session; ///< Representation of a session* The connection state ofthe specified session.* @param[in] session Your session object* @return The(sp_session