MongoDB.Bson.IO.BsonWriter.WriteStartDocument C# (CSharp) Method

        public virtual void WriteStartDocument()
        {
            _serializationDepth++;
            if (_serializationDepth > _settings.MaxSerializationDepth)
            {
                throw new BsonSerializationException("Maximum serialization depth exceeded (does the object being serialized have a circular reference?).");
            }
        }

        public override void Serialize(BsonWriter bsonWriter, Type nominalType, object value, IBsonSerializationOptions options)
        {
            IDictionary<string, object> obj = value as IDictionary<string, object>;
            if (obj == null)
            {
                bsonWriter.WriteNull();
                return;
            }

            bsonWriter.WriteStartDocument();
            foreach (var member in obj)
            {
                bsonWriter.WriteName(member.Key);
                object memberValue = member.Value;

                if (memberValue == null)
                {
                    bsonWriter.WriteNull();
                }
                else
                {
                    nominalType = memberValue.GetType();
                    var serializer = BsonSerializer.LookupSerializer(nominalType);
                    serializer.Serialize(bsonWriter, nominalType, memberValue, options);
                }
            }
            bsonWriter.WriteEndDocument();
        }