module Handler: Handler
type 'a t
val create : ('a -> unit) -> 'a t
create k creates a handler by coupling the continuation k together with the
evaluation context that is current at the time create is called. Whenever this
handler is later invoked, it will happen in this saved evaluation context.
val prepend : 'a t -> f:('b -> 'a) -> 'b t
prepend h ~f pre-composes the handler with the function f
val filter : 'a t -> f:('a -> bool) -> 'a t
filter h ~f makes the eventual execution of the handler h on a value v dependent
on whether predicate f holds of v
val install : 'a t -> 'a Deferred.t -> unit -> unit
install h d behaves like upon except that it also returns a uninstall function
that, when called, uninstalls the handler
val schedule : 'a t -> 'a -> unit
schedule h v schedules the handler h to run at some point in the future by being
called on value v