diff --git a/internal/timer/timer.go b/internal/timer/timer.go
index 52936564..0c060fee 100644
--- a/internal/timer/timer.go
+++ b/internal/timer/timer.go
@@ -4,6 +4,9 @@ import (
 	"time"
 )
 
+// Stop the timer and drain the channel.
+// Note that this should only be called if the channel hasn't already been
+// drained or it may block indefinitely.
 func StopTimer(t *time.Timer) {
 	if !t.Stop() {
 		// Need to drain the timer if Stop() returns false