Resume Download

The higher-layer protocol might resume the existing download; either it was interrupted through a Pause download event (section or some error occurred that was sent to the higher-layer protocol for further processing.

 If the higher-layer protocol passes authentication info
    populate AUTH_CREDENTIALS accordingly.

If DATA_TIMESTAMP is UNKNOWN, the client MAY set state to STATE_SIZE in order to determine the length of the URL prior to download; otherwise it MUST set it to STATE_DOWNLOAD.<29>