diff --git a/senders/client.go b/senders/client.go
index 327a747..4f97613 100644
--- a/senders/client.go
+++ b/senders/client.go
@@ -17,6 +17,7 @@ type Sender interface {
 	EventSender
 	internal.Flusher
 	Close()
+	private()
 }
 
 type wavefrontSender struct {
@@ -74,6 +75,9 @@ func (sender *wavefrontSender) Start() {
 	sender.eventHandler.Start()
 }
 
+func (sender *wavefrontSender) private() {
+}
+
 func (sender *wavefrontSender) SendMetric(name string, value float64, ts int64, source string, tags map[string]string) error {
 	line, err := metricLine(name, value, ts, source, tags, sender.defaultSource)
 	if err != nil {
diff --git a/senders/client_multi.go b/senders/client_multi.go
index 8f263a1..0a3bfcb 100644
--- a/senders/client_multi.go
+++ b/senders/client_multi.go
@@ -54,6 +54,9 @@ func NewMultiSender(senders ...Sender) MultiSender {
 	return ms
 }
 
+func (ms *multiSender) private() {
+}
+
 func (ms *multiSender) SendMetric(name string, value float64, ts int64, source string, tags map[string]string) error {
 	var errors multiError
 	for _, sender := range ms.senders {
diff --git a/senders/client_noop.go b/senders/client_noop.go
index 70cf30b..60d2cc9 100644
--- a/senders/client_noop.go
+++ b/senders/client_noop.go
@@ -17,6 +17,9 @@ func NewWavefrontNoOpClient() (Sender, error) {
 	return defaultNoopClient, nil
 }
 
+func (sender *wavefrontNoOpSender) private() {
+}
+
 func (sender *wavefrontNoOpSender) Start() {
 	// no-op
 }