UB_LIBCMD_CANCEL
sldns_write_uint32(p, UB_LIBCMD_CANCEL);
log_assert( sldns_read_uint32(p) == UB_LIBCMD_CANCEL);
case UB_LIBCMD_CANCEL:
sldns_write_uint32(p, UB_LIBCMD_CANCEL);
log_assert( sldns_read_uint32(p) == UB_LIBCMD_CANCEL);
case UB_LIBCMD_CANCEL: