diff --git a/codec/proto/proto.go b/codec/proto/proto.go
index 03ed329c..c4375ec2 100644
--- a/codec/proto/proto.go
+++ b/codec/proto/proto.go
@@ -33,6 +33,10 @@ func (c *Codec) ReadBody(b interface{}) error {
 }
 
 func (c *Codec) Write(m *codec.Message, b interface{}) error {
+	if b == nil {
+		// Nothing to write
+		return nil
+	}
 	p, ok := b.(proto.Message)
 	if !ok {
 		return codec.ErrInvalidMessage