(* TODO time
   uhuh!
   need to be int64 for binary/pg round trip *)

type t = Ptime.t option
type span = Ptime.Span.t option

val diff : t -> t -> span
val add_span_exn : t -> span -> t
val of_span_exn : span -> t

(* - *)
val jsont : t Jsont.t
val bin : t Bin.t
val bin_nbo : t Bin.t
val caqti : Ptime.t option Caqti_type.t