module EchoOnceServer: sig .. end
sig
end
val echo : 'a -> Async.Std.Reader.t -> Async.Std.Writer.t -> unit Async_kernel.Deferred.t
'a -> Async.Std.Reader.t -> Async.Std.Writer.t -> unit Async_kernel.Deferred.t
val main : unit -> unit Async.Std.Deferred.t
unit -> unit Async.Std.Deferred.t