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: filter.rb
    path of file: ./repos/fluentd/lib/fluent/compat
    
    the code of the file until where you have to start completion: #
# Fluentd
#
# 
    
      def start
        super

        if instance_variable_defined?(:@formatter) && @inject_config
          unless @formatter.class.ancestors.include?(Fluent::Compat::HandleTagAndTimeMixin)
            if @formatter.respond_to?(:owner) && !@formatter.owner
              @formatter.owner = self
              @formatter.singleton_class.prepend FormatterUtils::InjectMixin
            end