Stupid composite key implementation.

FoundationDbDemo1.cs

private static async Task Demo()
{
  var cancellationTokenSource = new CancellationTokenSource();
  using (var db = await Fdb.OpenAsync())
  {
    var partition = db.Partition("my_data");
    var firstId = Guid.NewGuid();
    var firstSequence = new[] { "foo", "bar", "baz" };

    // writing the data:
    using (var trans = db.BeginTransaction(cancellationTokenSource.Token))
    {
      var version = 0;
      foreach (var item in firstSequence)
      {
        trans.Set(
          partition.Pack<Guid, int>(firstId, ++version),
          partition.Pack<string>(item));
      }

      await trans.CommitAsync();
    }

    // get all items for a sequence:
    using (var trans = db.BeginTransaction(cancellationTokenSource.Token))
    {
      var range = trans.GetRange(FdbKeyRange.PrefixedBy(partition.Pack(firstId)));
      var items = range.Select(kv => kv.Value.ToTuple().Last());
      await items.ForEachAsync (Console.WriteLine);
      // output: foo, bar, baz
    }

    // get all items starting with the third:
    using (var trans = db.BeginTransaction(cancellationTokenSource.Token))
    {
      var range = trans.GetRange(
        FdbKeyRange.PrefixedBy(partition.Pack(firstId)));
      var items = range.Skip(2).Select(kv => kv.Value.ToTuple().Last());
      await items.ForEachAsync(Console.WriteLine);
      // output: baz
    }
  }
}