# File lib/powerbar.rb, line 378
    def initialize(at, window, max_interval=10, interval_step_up=0.1)
      super([])
      @last_sample_at = at
      @sample_interval = 0
      @sample_interval_step_up = interval_step_up
      @sample_interval_max = max_interval
      @counter = 0
      @window = window
    end