add skynet.trace_timeout(on), see #1098

test/testtimer.lua

@@ -13,6 +13,11 @@ end
 
 local function test()
 	skynet.timeout(10, function() print("test timeout 10") end)
+	local taskinfo = {}
+	skynet.task(taskinfo)
+	for session, info in pairs(taskinfo) do
+		print("session = ", session, "trace = ", info)
+	end
 	for i=1,10 do
 		print("test sleep",i,skynet.now())
 		skynet.sleep(1)
@@ -20,6 +25,7 @@ local function test()
 end
 
 skynet.start(function()
+	skynet.trace_timeout(true)	-- trun on trace for timeout, skynet.task will returns more info.
 	test()
 
 	skynet.fork(wakeup, coroutine.running())