Node.js Timers Module
Example
Write "Hello" every 500 milliseconds:
  var myInt = setInterval(function () {
    console.log("Hello");
  }, 500);
  Run example »
Definition and Usage
The Timers module provides a way scheduling functions to be called later at a given time.
The Timer object is a global object in Node.js, and it is not necessary to 
import it using the require keyword. 
Timers Methods
| Method | Description | 
|---|---|
| clearImmediate() | Cancels an Immediate object | 
| clearInterval() | Cancels an Interval object | 
| clearTimeout() | Cancels a Timeout object | 
| ref() | Makes the Timeout object active. Will only have an effect if the Timeout.unref() method has been called to make the Timeout object inactive. | 
| setImmediate() | Executes a given function immediately. | 
| setInterval() | Executes a given function at every given milliseconds | 
| setTimeout() | Executes a given function after a given time (in milliseconds) | 
| unref() | Stops the Timeout object from remaining active. | 

