public Song(string id, SongMetadata metadata, string fileId, SongCollection collection)
{
Id = id;
Metadata = metadata;
FileId = fileId;
this.collection = collection;
}
private async Task GetMetadata()
{
var info = await client.GetVideoAsync(videoId);
Metadata = new SongMetadata(info.Title, info.Author, info.GetUrl(), info.Duration);
}