diff --git a/io/vmessreader.go b/io/vmessreader.go
index 5a7744c1..957eeae9 100644
--- a/io/vmessreader.go
+++ b/io/vmessreader.go
@@ -4,7 +4,9 @@ import (
 	"net"
 )
 
-// VMessInput implements the input message of VMess protocol.
+// VMessInput implements the input message of VMess protocol. It only contains
+// the header of a input message. The data part will be handled by conection
+// handler directly, in favor of data streaming.
 type VMessInput struct {
 	version  byte
 	userHash [16]byte
@@ -14,19 +16,20 @@ type VMessInput struct {
 	command  byte
 	port     uint16
 	target   [256]byte
-	data     []byte
 }
 
 type VMessReader struct {
 	conn *net.Conn
 }
 
+// NewVMessReader creates a new VMessReader
 func NewVMessReader(conn *net.Conn) (VMessReader, error) {
 	var reader VMessReader
 	reader.conn = conn
 	return reader, nil
 }
 
+// Read reads data from current connection and form a VMessInput if possible.
 func (*VMessReader) Read() (VMessInput, error) {
 	var input VMessInput
 	return input, nil