public async Task Test_FdbBlob_Can_AppendToBlob()
        {
            using (var db = await OpenTestPartitionAsync())
            {
                var location = db.Root["BlobsFromOuterSpace"];
                await CleanLocation(db, location);

                var blob = new FdbBlob(location);

                Log("Insert blob in 3 chunks...");
                await blob.WriteAsync(db, async (tr, state) =>
                {
                    await state.AppendAsync(tr, Value("Attack"));
                    await state.AppendAsync(tr, Value(" of the "));
                    await state.AppendAsync(tr, Value("Blobs!"));
                }, this.Cancellation);

#if DEBUG
                await DumpSubspace(db, location);
#endif

                Log("Checking blob size...");
                long?size = await blob.ReadAsync(db, (tr, state) => state.GetSizeAsync(tr), this.Cancellation);

                Log($"> {size:N0}");
                Assert.That(size, Is.EqualTo(20));

                Log("Checking blob content...");
                var data = await blob.ReadAsync(db, (tr, state) => state.ReadAsync(tr, 0, (int)(size ?? 0)), this.Cancellation);

                Log($"> {data.Count:N0} bytes");
                Assert.That(data.ToUnicode(), Is.EqualTo("Attack of the Blobs!"));
            }
        }
        public async Task Test_FdbBlob_CanAppendLargeChunks()
        {
            using (var db = await OpenTestPartitionAsync())
            {
                var location = db.Root["BlobsFromOuterSpace"];
                await CleanLocation(db, location);

                var blob = new FdbBlob(location.ByKey("BigBlob"));

                var data = Slice.Zero(100_000);
                for (int i = 0; i < data.Count; i++)
                {
                    data.Array[data.Offset + i] = (byte)i;
                }

                Log("Construct blob by appending chunks...");
                for (int i = 0; i < 50; i++)
                {
                    await blob.WriteAsync(db, (tr, state) => state.AppendAsync(tr, data), this.Cancellation);
                }

                Log("Reading blob size:");
                long?size = await blob.ReadAsync(db, (tr, state) => state.GetSizeAsync(tr), this.Cancellation);;
                Log($"> {size:N0}");
                Assert.That(size, Is.EqualTo(50 * data.Count));

                Log("Reading blob content:");
                var s = await blob.ReadAsync(db, (tr, state) => state.ReadAsync(tr, 1234567, 1_000_000), this.Cancellation);

                Log($"> {s.Count:N0} bytes");
                Assert.That(s.Count, Is.EqualTo(1_000_000));

                // should contains the correct data
                for (int i = 0; i < s.Count; i++)
                {
                    if (s[i] != (byte)((1234567 + i) % data.Count))
                    {
                        Assert.Fail($"Corrupted blob chunk at {i}: {s[i, i + 128]}");
                    }
                }
            }
        }