* The most common mistake programmers make with timer.device is to send
    off a particular timerequest before the previous use of that
    timerequest has completed.  Use IO_Torture to catch this.

  * IO_QUICK requests may be deferred and be replied as documented.

  * VBLANK timer requests, as documented, now wait at least as long as
    the full number of VBlanks you asked for.  Previously, a partial
    vertical blank could count towards your requested number.  The new
    behavior is more correct and matches the docs, but it can cause
    VBlank requests to now take up to 1 VBlank longer under 2.0 as
    compared to 1.3. For example, a 1/10 second request, may take 6-7
    Vblanks instead of 5-6 VBlanks, or about 15% longer.