如何使用git2go / libgit2从Blob获取实际文件？

So this might be due to my ignorance of what git does under the hood, but I'm trying to clone a repo using git2go like you would with running git clone <repo url> in bash. I can clone the repo to get the content of the usual .git/ folder repos have. Then I am trying to get the actual project files from there. To do this I get the index of the repo returned from the clone, then I write a tree with that index. Then I get lost, but here's what I'm currently doing:

type Project struct {
    conf      config.Project
    State     string
    ABSPath   string
    Services  map[string]*Service
    creds     *credentials.RawCredentials
    gitCreds  *git.Cred
    clonePath string
    CloneOpts *git.CloneOptions
}

func (p *Project) Unpack(repo *git.Repository) error {
    index, indexErr := repo.Index()
    if indexErr != nil {
        return indexErr
    }
    log.Println(*index)
    oid, writeErr := index.WriteTree()
    if writeErr != nil {
        return writeErr
    }
    blob, blobErr := repo.LookupBlob(oid)
    if blobErr != nil {
        return blobErr
    }
    content := blob.Contents()
    log.Println((string)(content))
    return nil
}

Currently, content is empty. My goal here is to unpack the entire repo. I believe I need to walk through the working tree in order to do that. Am I headed in the right direction?