time: document that After uses memory until duration times out

Fixes #15698

Change-Id: I616fc06dcf04092bafdaf56fb1afba2a998a6d83
Reviewed-on: https://go-review.googlesource.com/23304
Reviewed-by: Ian Lance Taylor <iant@golang.org>

diff --git a/src/time/sleep.go b/src/time/sleep.go
index c348366604e6dbe33b8910d4e2a86b4f077094a2..7661f7e54fc1302f8d1e1e5f2a1365127cbac8f8 100644 (file)
--- a/src/time/sleep.go
+++ b/src/time/sleep.go
@@ -106,6 +106,9 @@ func sendTime(c interface{}, seq uintptr) {
 // After waits for the duration to elapse and then sends the current time
 // on the returned channel.
 // It is equivalent to NewTimer(d).C.
+// The underlying Timer is not recovered by the garbage collector
+// until the timer fires. If efficiency is a concern, use NewTimer
+// instead and call Timer.Stop if the timer is no longer needed.
 func After(d Duration) <-chan Time {
        return NewTimer(d).C
 }