/**
\example netled.cpp

The #Net object provides an easy-to-use mechanism allowing nodes to
offer services to each other, and to respond to service requests using
the ordinary reflex processing mechanism familiar from all SFB
programming.

In this simple 'net LED' sketch, the 'service' to be provided is
lighting the LED red or blue, for which the sketch defines service
code 'l' (ell).  A long button click on a board toggles whether that
board provides the 'l' service to the network, while a short button
click sends a 'toggle' request to the nearest 'l' service provider,
causing it to toggle its LED and send an appropriate reply.

When first encountering SFB networking, it's easy to confuse service
types (in this sketch, 'l'), with packet reflex types (in this sketch,
't' and 'r') -- but they are very different beasts.  Rather than
thinking of a service type as being similar to a packet type, a
network service type is better seen as similar to a face or a
direction: Just as you can send and receive any and all packet types
to and from your NORTH face, say, you can also send and receive any
packet types to and from service 'l'.

The difference, of course, is that you don't have to know where
service 'l' is actually being provided -- #Net will route your
requests and replies for you, via some shortest path through the grid.

 */
