title: UIScrollView touch handling
body: <p>I'm reading the following about UIScrollView from Apple UIScrollView Class Reference Documentation:</p>
  
  <blockquote>
    <p>Because a scroll view has no scroll
    bars, it must know whether a touch
    signals an intent to scroll versus an
    intent to track a subview in the
    content. To make this determination,
    it temporarily intercepts a touch-down
    event by starting a timer and, before
    the timer fires, seeing if the
    touching finger makes any movement. If
    the timer fires without a significant
    change in position, the scroll view
    sends tracking events to the touched
    subview of the content view. If the
    user then drags their finger far
    enough before the timer elapses, the
    scroll view cancels any tracking in
    the subview and performs the scrolling
    itself. Subclasses can override the
    touchesShouldBegin:withEvent:inContentView:,
    pagingEnabled, and
    touchesShouldCancelInContentView:
    methods (which are called by the
    scroll view) to affect how the scroll
    view handles scrolling gestures.</p>
  </blockquote>
  
  <p>I don't understand the sentence starting with "If the user then drags their finger far enough before the timer elapses..."  I thought the timer already fired according to the previous sentence.  Is it talking about another timer in this one?</p>