instance method read

# File activesupport/lib/active_support/cache/strategy/local_cache.rb, line 34
        def read(key, options = nil)
          value = local_cache && local_cache.read(key)
          if value == NULL
            nil
          elsif value.nil?
            value = super
            local_cache.mute { local_cache.write(key, value || NULL) } if local_cache
            value.duplicable? ? value.dup : value
          else
            # forcing the value to be immutable
            value.duplicable? ? value.dup : value
          end
        end