You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: formatter_csv.rb
    path of file: ./repos/fluentd/lib/fluent/plugin
    
    the code of the file until where you have to start completion: #
# Fluentd
#
#    Licensed under the Apache License, Version 2.0 (the "License");
#    you may not use this file except in compliance with the License.
#    You may obtain a copy of the License at
#
#        http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS,
#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#    See the License for the specific language governing permissions and
#   
    
      def format(tag, time, record)
        csv = (@cache[Thread.current] ||= CSV.new("".force_encoding(Encoding::ASCII_8BIT), **@generate_opts))
        line = (csv << record).string.dup
        # Need manual cleanup because CSV writer doesn't provide such method.
        csv.rewind
        csv.truncate(0)
        line
      end

      def format_with_nested_fields(tag, time, record)
        csv = (@cache[Thread.current] ||= CSV.new("".force_encoding(Encoding::ASCII_8BIT), **@generate_opts))
        values = @accessors.map { |a| a.call(record) }
        line = (csv << values).string.dup
        # Need manual cleanup because CSV writer doesn't provide such method.
        csv.rewind
        csv.truncate(0)
        line
      end
    end
  end