/**
  \example profile1.cpp 

  This sketch uses #Ticker to measure how time is spent during ten
  second time windows.  Each time through the loop() function, first
  #Ticker is reset, then a ten second delay is performed, and then the
  total number of microseconds assigned to various categories during
  that delay are reported.

  Typical output from this sketch, when running on an isolated cell
  (connected only via USB-serial to sfbprog), is: 
  <pre>
    143 2477 9837132
    119 2465 9837152
    182 2308 9837263
  </pre>
  while typical output from this sketch running on a cell that is
  connected to another cell, and also via USB-serial, is:
  <pre>
    339 1767 9837721
    239 1684 9837964
    250 1682 9837980
  </pre>

  Note that packet-handling time rises a bit, which makes sense, but
  that alarm load actually decreases!  Why?  It turns out, because
  'test packets' are sent on inactive faces to check for connections
  \e more \e often than 'keep-alive packets' are sent on active faces!

 */
