escape_key

# File activesupport/lib/active_support/cache/mem_cache_store.rb, line 160
        def escape_key(key)
          key = key.to_s.gsub(ESCAPE_KEY_CHARS){|match| "%#{match.getbyte(0).to_s(16).upcase}"}
          key = "#{key[0, 213]}:md5:#{Digest::MD5.hexdigest(key)}" if key.size > 250
          key
        end