--- a/util/async.lua	Sat Jul 07 21:55:18 2018 +0200
+++ b/util/async.lua	Sun Jul 08 00:37:01 2018 +0200
@@ -1,5 +1,6 @@
 local logger = require "util.logger";
 local log = logger.init("util.async");
+local timer = require "util.timer";
 local new_id = require "util.id".short;
 
 local function checkthread()
@@ -245,9 +246,16 @@
 	return pcall(checkthread);
 end
 
+local function sleep(s)
+	local wait, done = waiter();
+	timer.add_task(s, done);
+	wait();
+end
+
 return {
 	ready = ready;
 	waiter = waiter;
 	guarder = guarder;
 	runner = runner;
+	sleep = sleep;
 };

--- a/util/timer.lua	Sat Jul 07 21:55:18 2018 +0200
+++ b/util/timer.lua	Sun Jul 08 00:37:01 2018 +0200
@@ -10,7 +10,6 @@
 local log = require "util.logger".init("timer");
 local server = require "net.server";
 local get_time = require "util.time".now
-local async = require "util.async";
 local type = type;
 local debug_traceback = debug.traceback;
 local tostring = tostring;
@@ -104,16 +103,9 @@
 	return id;
 end
 
-local function sleep(s)
-	local wait, done = async.waiter();
-	add_task(s, done);
-	wait();
-end
-
 return {
 	add_task = add_task;
 	stop = stop;
 	reschedule = reschedule;
-	sleep = sleep;
 };