title: CountDownTimer not accurate
body: <p>I have an Android service running in the background.
  I want to be notified after a specific period of time (22 seconds), so I wrote:</p>
  
  <pre><code>private CountDownTimer mCountDownTimer = new CountDownTimer(22*1000,22*1000) {
  
      public void onTick(long millisUntilFinished) {}
  
      public void onFinish() {
          doSomething();
      }
  };
  </code></pre>
  
  <p>I run this, and get the notification after 40 seconds, and even 50 seconds. Am I doing something wrong? How can this be done?</p>