cache_control_headers

# File actionpack/lib/action_dispatch/http/cache.rb, line 145
        def cache_control_headers
          cache_control = {}

          cache_control_segments.each do |segment|
            directive, argument = segment.split("=", 2)

            if SPECIAL_KEYS.include? directive
              key = directive.tr("-", "_")
              cache_control[key.to_sym] = argument || true
            else
              cache_control[:extras] ||= []
              cache_control[:extras] << segment
            end
          end

          cache_control
        end