module Command: Commandinclude Core.Command
val async_basic : summary:string ->
       ?readme:(unit -> string) ->
       ('a, unit -> unit Import.Deferred.t) Spec.t -> 'a -> tasync_basic is exactly the same as Core.Command.basic, except that the function it
    wraps returns unit Deferred.t, instead of unit.  async_basic will also start the
    Async scheduler before the wrapped function is run, and will stop the scheduler when
    the wrapped function returns.Arg_type.t that uses auto-completion and uses async to compute the
    possible completions, one should use
      Arg_type.create ~complete of_string
    
    where complete wraps its async operations in Thread_safe.block_on_async.  With
    this, the complete function is only called when the executable is auto-completing,
    not for ordinary execution.  This improves performance, and also means that the async
    scheduler isn't started for ordinary execution of the command, which makes it possible
    for the command to daemonize (which requires the scheduler to not have been started).