```ruby
require 'cucumber'

module Flatware
  module Cucumber
    class Runtime < ::Cucumber::Runtime

      attr_accessor :configuration, :loader
      attr_reader :out, :err
      attr_reader :visitor

      def initialize(out=StringIO.new, err=out)
        @out, @err = out, err
        super(default_configuration)
        load_step_definitions
        @results = Results.new(configuration)
      end

      def default_configuration
        config = ::Cucumber::Cli::Configuration.new
        config.parse! []
        config
      end

      def run(feature_files=[])
        options = Array(feature_files) + %w[--format Flatware::Cucumber::Formatter]

        configure(::Cucumber::Cli::Main.new(options, out, err).configuration)

        self.visitor = configuration.build_tree_walker(self)
        visitor.visit_features(features)
        results
      end

      private
      def features
        @loader = nil
        super
      end
    end
  end
end
```

Allow features to be cached throughout run call
user
```ruby
require 'cucumber'

module Flatware
  module Cucumber
    class Runtime < ::Cucumber::Runtime

      attr_accessor :configuration, :loader
      attr_reader :out, :err
      attr_reader :visitor

      def initialize(out=StringIO.new, err=out)
        @out, @err = out, err
        super(default_configuration)
        load_step_definitions
        @results = Results.new(configuration)
      end

      def default_configuration
        config = ::Cucumber::Cli::Configuration.new
        config.parse! []
        config
      end

      def run(feature_files=[])
        @loader = nil
        options = Array(feature_files) + %w[--format Flatware::Cucumber::Formatter]

        configure(::Cucumber::Cli::Main.new(options, out, err).configuration)

        self.visitor = configuration.build_tree_walker(self)
        visitor.visit_features(features)
        results
      end
    end
  end
end
```
assistant