Schedule jobs to run at a time in the future.
The underlying implementation uses a heap of events, one for each job that needs to run in the future. The Async scheduler is responsible for waking up at the right time to run the jobs.
module Deferred = Async_kernel__.Deferred1
module type Clock : sig ... end
module type Clock_deprecated : sig ... end
Clock_deprecated
is used in Require_explicit_time_source
to create a clock
module in which all functions are deprecated.