$hash_nor_ref->{ref} = {} ; #will have REFCNT = 0 on clean
$hash_nor_ref->{ref} = [] ; #will have REFCNT = 0 on clean
$hash_nor_ref->{ref} = \'' ; #will have REFCNT = 1 on clean
$hash_nor_ref->{ref} = bless({}) ; #before destroy have a reference to a blessed HASH, after destroy it will have a reference to a SCALAR, with REFCNT = 1.