Does Gambit have the ability to make custom ports from arbitrary closures?

What do these do:

 > (apropos "generic")
"##" namespace:
   generic-hash, open-file-generic, open-file-generic-from-psettings,
open-process-generic, open-string-generic, open-string-pipe-generic,
open-u8vector-generic,
   open-u8vector-pipe-generic, open-vector-generic,
open-vector-pipe-generic, write-generic-to-character-port