An event is a value that will at some point in time (possibly the past, possibly the future) transition from "undetermined" to "determined", with some value. One can wait_for an event in a computation.
type'a t
val sexp_of_t : ( 'a->Sexplib0.Sexp.t )->'at->Sexplib0.Sexp.t
val value : 'at->'aDigital_components__Import.Option.t