成员的完整列表，这些成员属于 aiot_mqtt_upload_desc_t,包括所有继承而来的类成员

block_size	aiot_mqtt_upload_desc_t
code	aiot_mqtt_upload_desc_t
complete	aiot_mqtt_upload_desc_t
file_name	aiot_mqtt_upload_desc_t
file_offset	aiot_mqtt_upload_desc_t
file_size	aiot_mqtt_upload_desc_t
message	aiot_mqtt_upload_desc_t
upload_id	aiot_mqtt_upload_desc_t