Need way to "dup" an rdataset (i.e. different rdataset handle, same underlying

data).

DB addnode routine should take an rdataset *, which, if non-NULL, would be

attached to the added rdataset.

Need credibility, security status.

Cache security status in rdataset. Have rdataset supply methods to get/set

the security status. For RBTDB, it goes something like this:

get:

if (cached status == pending)

lock node lock

read rdataset's status

unlock node lock

update cached status

return (cached status)

set:

require that status cannot go backwards (e.g. OK to pending)

lock node lock

write rdataset's status

unlock node lock

update cached status