support packet transfer type in mux

common/serial/numbers.go

@@ -1,6 +1,7 @@
 package serial
 
 import "strconv"
+import "io"
 
 // Uint16ToBytes serializes an uint16 into bytes in big endian order.
 func Uint16ToBytes(value uint16, b []byte) []byte {
@@ -11,6 +12,14 @@ func Uint16ToString(value uint16) string {
 	return strconv.Itoa(int(value))
 }
 
+func ReadUint16(reader io.Reader) (uint16, error) {
+	var b [2]byte
+	if _, err := io.ReadFull(reader, b[:]); err != nil {
+		return 0, err
+	}
+	return BytesToUint16(b[:]), nil
+}
+
 func WriteUint16(value uint16) func([]byte) (int, error) {
 	return func(b []byte) (int, error) {
 		b = Uint16ToBytes(value, b[:0])