public async Task WriteOidAsync()
        {
            MemoryStream ms     = new MemoryStream();
            BsonWriter   writer = new BsonWriter(ms);

            byte[] oid = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 };

            await writer.WriteStartObjectAsync();

            await writer.WritePropertyNameAsync("_oid");

            writer.WriteObjectId(oid);
            await writer.WriteEndObjectAsync();

            string bson = BytesToHex(ms.ToArray());

            Assert.AreEqual("17-00-00-00-07-5F-6F-69-64-00-01-02-03-04-05-06-07-08-09-0A-0B-0C-00", bson);

            ms.Seek(0, SeekOrigin.Begin);
            BsonReader reader = new BsonReader(ms);

            Assert.IsTrue(await reader.ReadAsync());
            Assert.AreEqual(JsonToken.StartObject, reader.TokenType);

            Assert.IsTrue(await reader.ReadAsync());
            Assert.AreEqual(JsonToken.PropertyName, reader.TokenType);

            Assert.IsTrue(await reader.ReadAsync());
            Assert.AreEqual(JsonToken.Bytes, reader.TokenType);
            CollectionAssert.AreEquivalent(oid, (byte[])reader.Value);

            Assert.IsTrue(await reader.ReadAsync());
            Assert.AreEqual(JsonToken.EndObject, reader.TokenType);
        }
        public async Task WriteBytesAsync()
        {
            byte[] data = Encoding.UTF8.GetBytes("Hello world!");

            MemoryStream ms     = new MemoryStream();
            BsonWriter   writer = new BsonWriter(ms);
            await writer.WriteStartArrayAsync();

            await writer.WriteValueAsync("a");

            await writer.WriteValueAsync("b");

            await writer.WriteValueAsync(data);

            await writer.WriteEndArrayAsync();

            await writer.FlushAsync();

            ms.Seek(0, SeekOrigin.Begin);

            string expected =
                "2B-00-00-00-02-30-00-02-00-00-00-61-00-02-31-00-02-00-00-00-62-00-05-32-00-0C-00-00-00-00-48-65-6C-6C-6F-20-77-6F-72-6C-64-21-00";
            string bson = BytesToHex(ms.ToArray());

            Assert.AreEqual(expected, bson);

            BsonReader reader = new BsonReader(new MemoryStream(ms.ToArray()));

            reader.ReadRootValueAsArray = true;
            await reader.ReadAsync();

            await reader.ReadAsync();

            await reader.ReadAsync();

            await reader.ReadAsync();

            Assert.AreEqual(JsonToken.Bytes, reader.TokenType);
            CollectionAssert.AreEquivalent(data, (byte[])reader.Value);
        }
        public async Task WriteBigIntegerAsync()
        {
            BigInteger i = BigInteger.Parse("1999999999999999999999999999999999999999999999999999999999990");

            MemoryStream ms     = new MemoryStream();
            BsonWriter   writer = new BsonWriter(ms);

            await writer.WriteStartObjectAsync();

            await writer.WritePropertyNameAsync("Blah");

            await writer.WriteValueAsync(i);

            await writer.WriteEndObjectAsync();

            string bson = BytesToHex(ms.ToArray());

            Assert.AreEqual("2A-00-00-00-05-42-6C-61-68-00-1A-00-00-00-00-F6-FF-FF-FF-FF-FF-FF-1F-B2-21-CB-28-59-84-C4-AE-03-8A-44-34-2F-4C-4E-9E-3E-01-00", bson);

            ms.Seek(0, SeekOrigin.Begin);
            BsonReader reader = new BsonReader(ms);

            Assert.IsTrue(await reader.ReadAsync());
            Assert.AreEqual(JsonToken.StartObject, reader.TokenType);
            Assert.IsTrue(await reader.ReadAsync());
            Assert.AreEqual(JsonToken.PropertyName, reader.TokenType);

            Assert.IsTrue(await reader.ReadAsync());
            Assert.AreEqual(JsonToken.Bytes, reader.TokenType);
            CollectionAssert.AreEqual(new byte[] { 246, 255, 255, 255, 255, 255, 255, 31, 178, 33, 203, 40, 89, 132, 196, 174, 3, 138, 68, 52, 47, 76, 78, 158, 62, 1 }, (byte[])reader.Value);
            Assert.AreEqual(i, new BigInteger((byte[])reader.Value));

            Assert.IsTrue(await reader.ReadAsync());
            Assert.AreEqual(JsonToken.EndObject, reader.TokenType);

            Assert.IsFalse(await reader.ReadAsync());
        }
        public async Task WriteDateTimesAsync()
        {
            MemoryStream ms     = new MemoryStream();
            BsonWriter   writer = new BsonWriter(ms);

            writer.DateTimeKindHandling = DateTimeKind.Unspecified;

            await writer.WriteStartArrayAsync();

            await writer.WriteValueAsync(new DateTime(2000, 10, 12, 20, 55, 0, DateTimeKind.Utc));

            await writer.WriteValueAsync(new DateTime(2000, 10, 12, 20, 55, 0, DateTimeKind.Local));

            await writer.WriteValueAsync(
                new DateTime(2000, 10, 12, 20, 55, 0, DateTimeKind.Unspecified)
                );

            await writer.WriteEndArrayAsync();

            ms.Seek(0, SeekOrigin.Begin);

            BsonReader reader = new BsonReader(ms);

            reader.ReadRootValueAsArray = true;
            reader.DateTimeKindHandling = DateTimeKind.Utc;

            Assert.IsTrue(await reader.ReadAsync());
            Assert.AreEqual(JsonToken.StartArray, reader.TokenType);

            Assert.IsTrue(await reader.ReadAsync());
            Assert.AreEqual(JsonToken.Date, reader.TokenType);
            Assert.AreEqual(new DateTime(2000, 10, 12, 20, 55, 0, DateTimeKind.Utc), reader.Value);

            Assert.IsTrue(await reader.ReadAsync());
            Assert.AreEqual(JsonToken.Date, reader.TokenType);
            Assert.AreEqual(new DateTime(2000, 10, 12, 20, 55, 0, DateTimeKind.Utc), reader.Value);

            Assert.IsTrue(await reader.ReadAsync());
            Assert.AreEqual(JsonToken.Date, reader.TokenType);
            Assert.AreEqual(new DateTime(2000, 10, 12, 20, 55, 0, DateTimeKind.Utc), reader.Value);

            Assert.IsTrue(await reader.ReadAsync());
            Assert.AreEqual(JsonToken.EndArray, reader.TokenType);

            Assert.IsFalse(await reader.ReadAsync());
        }
        public async Task WriteReadEmptyAndNullStringsAsync()
        {
            MemoryStream ms     = new MemoryStream();
            BsonWriter   writer = new BsonWriter(ms);

            await writer.WriteStartArrayAsync();

            await writer.WriteValueAsync("Content!");

            await writer.WriteValueAsync("");

            await writer.WriteValueAsync((string)null);

            await writer.WriteEndArrayAsync();

            ms.Seek(0, SeekOrigin.Begin);

            BsonReader reader = new BsonReader(ms);

            reader.ReadRootValueAsArray = true;

            Assert.IsTrue(await reader.ReadAsync());
            Assert.AreEqual(JsonToken.StartArray, reader.TokenType);

            Assert.IsTrue(await reader.ReadAsync());
            Assert.AreEqual(JsonToken.String, reader.TokenType);
            Assert.AreEqual("Content!", reader.Value);

            Assert.IsTrue(await reader.ReadAsync());
            Assert.AreEqual(JsonToken.String, reader.TokenType);
            Assert.AreEqual("", reader.Value);

            Assert.IsTrue(await reader.ReadAsync());
            Assert.AreEqual(JsonToken.Null, reader.TokenType);
            Assert.AreEqual(null, reader.Value);

            Assert.IsTrue(await reader.ReadAsync());
            Assert.AreEqual(JsonToken.EndArray, reader.TokenType);

            Assert.IsFalse(await reader.ReadAsync());
        }