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: browser_file.go
    path of file: ./repos/client/go/kbfs/libgit
    
    the code of the file until where you have to start completion: // Copyright 2018 Keybase Inc. All rights reserved.
// Use of this source code is governed by a BSD
// license that can be found in the LICENSE file.

package libgit

import (
	"io"

	"github.com/pkg/errors"
	billy "gopkg.in/src-d/go-billy.v4"
	"gopkg.in/src-d/go-git.v4/plumbing/object"
)

const (
	browserFileDefaultMaxBufSize = 4 * 1024 * 1024 // 4 MB
)

type browserFile struct {
	f          *object.File
	r          io.ReadCloser
	maxBufSize int64
}

var _ billy.File = (*browserFile)(nil)

func newBrowserFile(f *object.File) (*browserFile, error) {
	r, err := f.Reader()
	if err != nil {
		return nil, err
	}
	return &browserFile{
		f:          f,
		r:          r,
		m
    
func (bf *browserFile) ReadAt(p []byte, off int64) (n int, err error) {
	// Sadly go-git doesn't expose a `ReadAt` or `Seek` interface for
	// this, but we can probably implement it if needed.  Instead, use
	// a new Reader object and just scan starting from the beginning.
	r, err := bf.f.Reader()
	if err != nil {
		return 0, err
	}
	defer func() {
		_ = r.Close()
	}()

	dataToSkip := off
	bufSize := dataToSkip
	if bufSize > bf.maxBufSize {
		bufSize = bf.maxBufSize
	}
	buf := make([]byte, bufSize)

	// Skip past the data we don't care about, one chunk at a time.
	for dataToSkip > 0 {
		toRead := int64(len(buf))
		if dataToSkip < toRead {
			toRead = dataToSkip
		}

		// Throwaway data.
		n, err := r.Read(buf[:toRead])
		if err != nil {
			return 0, err
		}
		dataToSkip -= int64(n)
	}

	return r.Read(p)
}