Used to calculate the time to execute the next transfer. The
    EVERY clause is optional. If you specify the EVERY clause, you
    must specify either every-delta-time or every-absolute-time. If
    you omit the EVERY clause, the transfer occurs only once.

    The valid specification for every-delta-time is the delta format
    used by the $BINTIM OpenVMS system service. The delta time you
    specify is the time from the completion of the last transfer
    sequence until the start of the next one. A transfer sequence
    is the set of transfers from the first attempt until one of the
    following conditions is met: the execution is successful, the
    maximum number of retries specified in the RETRY clause has been
    reached, or a fatal error has occurred (one for which retries are
    not attempted).