- creating a new entity should be on creation of `?e :db/id ?v`, currently it's when a
entity id is encoded
- how to retract?
do you have to encode in order to retract?
or i guess try to lookup the values and quit if they don't exist? kind of extra busy
work ...
- how to update? (amend?)
something about reference counting encoded values and removing them when they are no
longer in use ...