diff --git a/common/mux/server_test.go b/common/mux/server_test.go
index 4158bf46..8649a067 100644
--- a/common/mux/server_test.go
+++ b/common/mux/server_test.go
@@ -90,7 +90,8 @@ func TestRegressionOutboundLeak(t *testing.T) {
 	}
 
 	{
-		b := buf.FromBytes([]byte("hello"))
+		b := buf.New()
+		b.Write([]byte("hello"))
 		common.Must(muxClientDownlink.Writer.WriteMultiBuffer(buf.MultiBuffer{b}))
 	}
 
@@ -102,7 +103,8 @@ func TestRegressionOutboundLeak(t *testing.T) {
 	}
 
 	{
-		b := buf.FromBytes([]byte("world"))
+		b := buf.New()
+		b.Write([]byte("world"))
 		common.Must(websiteUplink.Writer.WriteMultiBuffer(buf.MultiBuffer{b}))
 	}
 
diff --git a/common/mux/writer.go b/common/mux/writer.go
index e9c113cb..3a7161b5 100644
--- a/common/mux/writer.go
+++ b/common/mux/writer.go
@@ -78,9 +78,17 @@ func writeMetaWithFrame(writer buf.Writer, meta FrameMetadata, data buf.MultiBuf
 	if _, err := serial.WriteUint16(frame, uint16(data.Len())); err != nil {
 		return err
 	}
-
 	mb2 := make(buf.MultiBuffer, 0, len(data)+1)
 	mb2 = append(mb2, frame)
+	for _, b := range data {
+		if frame.Len() + b.Len() < buf.Size {
+			frame.Write(b.Bytes())
+			b.Release()
+			b = nil
+		} else {
+			break;
+		}
+	}
 	mb2 = append(mb2, data...)
 	return writer.WriteMultiBuffer(mb2)
 }