You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: encoder.go
    path of file: ./repos/devspace/vendor/gopkg.in/src-d/go-git.v4/plumbing/format/pktline
    
    the code of the file until where you have to start completion: // Package pktline implements reading payloads form pkt-lines and encoding
// pkt-lines from payloads.
package pktline

import (
	"bytes"
	"errors"
	"fmt"
	"io"
)

// An Encoder writes pkt-lines
    
func asciiHex16(n int) []byte {
	var ret [4]byte
	ret[0] = byteToASCIIHex(byte(n & 0xf000 >> 12))
	ret[1] = byteToASCIIHex(byte(n & 0x0f00 >> 8))
	ret[2] = byteToASCIIHex(byte(n & 0x00f0 >> 4))
	ret[3] = byteToASCIIHex(byte(n & 0x000f))

	return ret[:]
}