def []=(key, data)
      info, _ = read(key)
      info ||= {}

      if data
        write(key, data, info)
      else
        delete(key, info)
      end
    end
def []=(key, data)
      info, _ = read(key)
      info ||= {}

      if data
        write(key, data, info)
      else
        delete(key, info)
      end
    end
Write data to entry key, or updating existing one if it exists.

 @param [String] key
 @param [String] data