raft: describe the purpose of lockedRand
Struct lockedRand wraps rand.Rand with mutex lock because it's
accessed by multiple raft groups.
@@ -72,8 +72,8 @@ const (
var ErrProposalDropped = errors.New("raft proposal dropped")
// lockedRand is a small wrapper around rand.Rand to provide
-// synchronization. Only the methods needed by the code are exposed
-// (e.g. Intn).
+// synchronization among multiple raft groups. Only the methods needed
+// by the code are exposed (e.g. Intn).
type lockedRand struct {
mu sync.Mutex
rand *rand.Rand
