-- | /O(1)/ (Vector k) with exactly one element
singleton :: G.Vector (Vector k) (Rec (TaggedFunctor Identity) rs)
  => Rec (TaggedFunctor Identity) rs -> (Vector k) (Rec (TaggedFunctor Identity) rs)
singleton = G.singleton
singleton :: G.Vector (Vector k) (Rec (TaggedFunctor Identity) rs)
  => Rec (TaggedFunctor Identity) rs -> (Vector k) (Rec (TaggedFunctor Identity) rs)
singleton = G.singleton
singleton = G.singleton