# File lib/mongo/protocol/serializers.rb, line 324
        def self.serialize(buffer, value, max_bson_size = nil, validating_keys = BSON::Config.validating_keys?)
          start_size = buffer.length
          value.to_bson(buffer, validating_keys)
          if max_bson_size && buffer.length - start_size > max_bson_size
            raise Error::MaxBSONSize.new(max_bson_size)
          end
        end