This Source Code Form is subject to the terms of the Mozilla Public License,
v.2.0. If a copy of the MPL was not distributed with this file, You can obtain
one at http://mozilla.org/MPL/2.0/.
This module contains utilities to reduce the boilerplate when implementing a
FSM.
# Callback Builder
Useful to generate the callbacks that control the actions to perform in an FSM
or the state transitions.