Nonvirtual member functions

• void start() - Start the Timer accumulating time.
• void stop() - Stop the Timer from accumulating time.
• void clear() - Clear the accumulated time for the Timer.
• float clock_time() - Get the accumulated clock time for the Timer.
• float user_time() - Get the accumulated user CPU time.
• float system_time() - Get the accumulated system CPU time.
• float cpu_time() - Get the accumulated CPU time. This is user_time() + system_time().