/// <summary>
/// Adds a file to the output,
/// </summary>
/// <param name="filename">The name of the file to record</param>
/// <param name="lastModified">The value of the lastModified timestamp</param>
/// <param name="database">The database to use</param>
/// <param name="streamblockchannel">The channel to write blocks to</param>
/// <param name="meta">The metadata ti record</param>
private static async Task AddSymlinkToOutputAsync(string filename, DateTime lastModified, IMetahash meta, BackupDatabase database, IWriteChannel <StreamBlock> streamblockchannel)
{
var metadataid = await AddMetadataToOutputAsync(filename, meta, database, streamblockchannel).ConfigureAwait(false);
await database.AddSymlinkEntryAsync(filename, metadataid.Item2, lastModified);
}