Function mcl_transfer_set_arg 

pub unsafe extern "C" fn mcl_transfer_set_arg(
    t_hdl: *mut mcl_transfer,
    idx: u64,
    addr: *mut c_void,
    size: size_t,
    offset: off_t,
    flags: u64,
) -> c_int

@brief Sets up an argument for a transfer handle. Same as mcl_task_set_arg but for a transfer.

@param t_hdl The transfer handle created by mcl_transfer_create @param idx The index of the argument in the transfer list @param addr Address of the data @param size Size of the data @param flags Argument flags. Same as mcl_task_st_arg @return int 0 on succes, otherwise an error code