Setting rate policies

If you want to change the input value once the keyboard is completely released for some time.

1. Define the debounce policy in the getRatePolicy method to limit the rate at which a function can fire, which allows a delay before telling Shiny to read the new value

getRatePolicy: function() {
  return {
    policy: 'debounce', # direct or throttle
    delay: 250
  };
},