private static string GetRepositorySnapshotHash(GitPreparer gitPreparer)
        {
            var repositorySnapshot = gitPreparer.WithRepository(repo => {
                var head = repo.Head;
                if (head.Tip == null)
                {
                    return(head.CanonicalName);
                }
                var hash = string.Join(":", head.CanonicalName, head.Tip.Sha);
                return(hash);
            });

            return(GetHash(repositorySnapshot));
        }