Would be awesome to have an attribute that draws an ASCII picture of the resulting tree

[matthewgapp]

Thinking something like

#[state_machine(visualize)]
impl MyStruct { ... } 

fn main() { 
  let mut state_machine = Blinky::default().uninitialized_state_machine().init();
  let ascii_visualization: String = state_machine.visualize();
  println!("{}", ascii_visualiztion);
}

Which would print something like

                          ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐             
                                    Top                       
                          └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘             
                                     │                        
                        ┌────────────┴────────────┐           
                        │                         │           
             ┌─────────────────────┐   ╔═════════════════════╗
             │      Blinking       │   ║     NotBlinking     ║
             │─────────────────────│   ╚═════════════════════╝
             │ counter: &'a usize  │                          
             └─────────────────────┘                          
                        │                                     
           ┌────────────┴────────────┐                        
           │                         │                        
╔═════════════════════╗   ╔═════════════════════╗             
║        LedOn        ║   ║        LedOff       ║             
║─────────────────────║   ║─────────────────────║             
║ counter: usize      ║   ║ counter: usize      ║             
╚═════════════════════╝   ╚═════════════════════╝