module Config:sig..end
    These can be set by setting an environment variable, ASYNC_CONFIG, to a sexp
    representation of the config.  Also, setting ASYNC_CONFIG to an invalid sexp
    (e.g. the empty string), will cause your program to print to stderr a usage message
    describing how to configure ASYNC_CONFIG, and exit nonzero.  For example, the
    following shell command should print the usage message:
ASYNC_CONFIG= foo.exe
module Epoll_max_ready_events:Validatedwith type raw := int
module Max_inter_cycle_timeout:Validatedwith type raw := Time.Span.t
module Max_num_open_file_descrs:Validatedwith type raw := int
module Max_num_threads:Validatedwith type raw := int
module Max_num_jobs_per_priority_per_cycle:Validatedwith type raw := int
type t 
val t : tval environment_variable : stringmodule Print_debug_messages_for:sig..end
module File_descr_watcher:sig..end
val abort_after_thread_pool_stuck_for : Core.Std.Time.Span.tval check_invariants : boolval detect_invalid_access_from_thread : boolval epoll_max_ready_events : Epoll_max_ready_events.tval file_descr_watcher : File_descr_watcher.tval max_inter_cycle_timeout : Max_inter_cycle_timeout.tval max_num_jobs_per_priority_per_cycle : Max_num_jobs_per_priority_per_cycle.tval max_num_open_file_descrs : Max_num_open_file_descrs.tval max_num_threads : Max_num_threads.tval record_backtraces : boolval report_thread_pool_stuck_for : Core.Std.Time.Span.tval timing_wheel_config : Core.Std.Timing_wheel.Config.tval sexp_of_t : t -> Sexplib.Sexp.t