Progress: Use reference to sync.Once

src/restic/progress.go

@@ -19,7 +19,7 @@ type Progress struct {
 	start      time.Time
 	c          *time.Ticker
 	cancel     chan struct{}
-	o          sync.Once
+	o          *sync.Once
 	d          time.Duration
 	lastUpdate time.Time
 
@@ -52,7 +52,7 @@ func (p *Progress) Start() {
 		return
 	}
 
-	p.o = sync.Once{}
+	p.o = &sync.Once{}
 	p.cancel = make(chan struct{})
 	p.running = true
 	p.Reset()