Event channels handlers.

type event

identifies the an event notification received from xen

val program_start : event

represents an event which 'fired' when the program started

val after : Eventchn.t -> event -> event Lwt.t

next channel event blocks until the system receives an event newer than event on channel channel. If an event is received while we aren't looking then this will be remembered and the next call to after will immediately unblock. If the system is suspended and then resumed, all event channel bindings are invalidated and this function will fail with Generation.Invalid