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: gitfs.go
    path of file: ./repos/flipt/internal/gitfs
    
    the code of the file until where you have to start completion: package gitfs

import (
	"errors"
	"fmt"
	"io"
	"io/fs"
	"time"

	"github.com/go-git/go-git/v5"
	"github.com/go-git/go-git/v5/plumbing"
	"github.com/go-git/go-git/v5/plumbing/filemode"
	"github.com/go-git/go-git/v5/plumbing
    
func NewFromRepoHash(logger *zap.Logger, repo *git.Repository, hash plumbing.Hash) (FS, error) {
	commit, err := repo.CommitObject(hash)
	if err != nil {
		return FS{}, fmt.Errorf("fetching commit (%q): %w", hash, err)
	}

	tree, err := repo.TreeObject(commit.TreeHash)
	if err != nil {
		return FS{}, fmt.Errorf("retrieving root tree (%q): %w", commit.TreeHash, err)
	}

	return New(logger.With(zap.Stringer("SHA", hash)), repo.Storer, tree), nil
}