AsyncCpsTree

apply runtime await. If this CpsTree is adync lambda f: x1...xn => F[y] transform one to f' = summon[RuntiemAwait[F].await(f(x1..xN))(monad,monad-context)] and return CpsTree with f' in unpure otherwise - unchanged or throw error TODO: move to Lambda

precondition: kind <: AsyncLambda(*)

is this is a sync-tree ?

let we have block {A; B} cps({A;B}) = cps(A).appendInBlock(cps(B))

origin term, used for diagnostics. TODO: only pos ?

owner of term. At first this is the owner at origin, than can be changed via changeOwner