Add a seed to authentication packet, and a hash of 256 bits
NetWorkSystem runs pipelines of functions.

Workers are transformed into lambda functions stored in named lists.
These lists define chains. Each chain can call another chain by
requesting a scheduled task.

Inside a chain, the same thread runs all the functions. The return code
of the function tells if the thread must continue or stop processing the
chain.

The ThreadPool class manage threads and block them until a task is
scheduled. It limits the number of concurrent active threads.