clear logic in v2io.Pipe

common/io/transport.go

@@ -3,12 +3,16 @@ package io
 func Pipe(reader Reader, writer Writer) error {
 	for {
 		buffer, err := reader.Read()
-		if buffer.Len() > 0 {
+		if err != nil {
-			err = writer.Write(buffer)
+			return nil
-		} else {
-			buffer.Release()
 		}
 
+		if buffer.IsEmpty() {
+			buffer.Release()
+			continue
+		}
+
+		err = writer.Write(buffer)
 		if err != nil {
 			return nil
 		}