defapply[S <: Sys[S], U, A](value: A with Publisher[S, U])(observe: (Observation.apply.S.Tx) ⇒ (U) ⇒ Unit)(implicit tx: Observation.apply.S.Tx, serializer: Serializer[Observation.apply.S.Tx, Observation.apply.S.Acc, A with Publisher[S, U]]): Observation[S, A]