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: nickname.go
    path of file: ./repos/minicron/client/vendor/golang.org/x/text/secure/precis
    
    the code of the file until where you have to start completion: // Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package precis

import (
	"unicode"
	"unicode/utf8"

	"golang.org/x/text/transform"
)

type nickAdditionalMapping struct {
	// TODO: This transformer needs to be stateless somehow…
	notStart  bool
	prevSpace bool
}

func (t *nickAdditionalMapping) Reset() {
	t.prevSpace = false
	t.notStart = false
}

func (t *nickAdditionalMapping) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
	// RFC 8266 §2.1.  Rules
	//
	// 2.  Additional Mapping Rule: The additional mapping rule consists of
	//     the following sub-rules.
	//
	//     a.  Map any instances of non-ASCII space to SPACE (U+0020); a
	//         non-ASCII space is any Unicode code point having a general
	//         category of "Zs", naturally with the exception of SPACE
	//         (U+0020).  (The inclusion of only ASCII space prevents
	//         confusion with various non-ASCII space code points, many of
	//         which are difficult to reproduce across different input
	//         methods.)
	//
	//     b.  Remove any instances of the ASCII space character at the
	//         beginning or end of a nickname (e.g., "stpeter " is mapped to
	//         "stpeter").
	//
	//     c.  Map interior sequences of more th
    
func (t *nickAdditionalMapping) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
	// RFC 8266 §2.1.  Rules
	//
	// 2.  Additional Mapping Rule: The additional mapping rule consists of
	//     the following sub-rules.
	//
	//     a.  Map any instances of non-ASCII space to SPACE (U+0020); a
	//         non-ASCII space is any Unicode code point having a general
	//         category of "Zs", naturally with the exception of SPACE
	//         (U+0020).  (The inclusion of only ASCII space prevents
	//         confusion with various non-ASCII space code points, many of
	//         which are difficult to reproduce across different input
	//         methods.)
	//
	//     b.  Remove any instances of the ASCII space character at the
	//         beginning or end of a nickname (e.g., "stpeter " is mapped to
	//         "stpeter").
	//
	//     c.  Map interior sequences of more than one ASCII space character
	//         to a single ASCII space character (e.g., "St  Peter" is
	//         mapped to "St Peter").
	for nSrc < len(src) {
		r, size := utf8.DecodeRune(src[nSrc:])
		if size == 0 { // Incomplete UTF-8 encoding
			if !atEOF {
				return nDst, nSrc, transform.ErrShortSrc
			}
			size = 1
		}
		if unicode.Is(unicode.Zs, r) {
			t.prevSpace = true
		} else {
			if t.prevSpace && t.notStart {
				dst[nDst] = ' '
				nDst += 1
			}
			if size != copy(dst[nDst:], src[nSrc:nSrc+size]) {
				nDst += size
				return nDst, nSrc, transform.ErrShortDst
			}
			nDst += size
			t.prevSpace = false
			t.notStart = true
		}
		nSrc += size
	}
	return nDst, nSrc, nil
}