diff --git a/metric/metric.go b/metric/metric.go
index bad70fc..f7ad057 100644
--- a/metric/metric.go
+++ b/metric/metric.go
@@ -59,6 +59,8 @@ type metric_empty struct{}
 func (mw *metric_empty) Set(newval int64) {}
 func (mw *metric_empty) Add(inc int64)    {}
 
+var MetricWriterNil = MetricWriter(&metric_empty{})
+
 type metric_int64 struct {
 	valptr     *int64
 	key        string