timers.go

package main

import (
	"fmt"
	"time"
)

// We often want to execute Go code at some point in the future,
// or repeatedly at some interval. Go’s built-in timer and ticker features make both of these tasks easy.
// We’ll look first at timers and then at tickers.

// Timer function ilustrate timers in go
func Timer() {
	// Timers represent a single event in the future.
	// You tell the timer how long you want to wait,
	// and it provides a channel that will be notified at that time.
	// This timer will wait 2 seconds.

	timer1 := time.NewTimer(2 * time.Second)

	// The <-timer1.C blocks on the timer’s channel C until it sends a value indicating that the timer expired.
	<-timer1.C
	fmt.Println("Timer 1 expired")

	// If you just wanted to wait, you could have used time.Sleep.
	// One reason a timer may be useful is that you can cancel the timer before it expires.
	// Here’s an example of that.
	timer2 := time.NewTimer(time.Second)
	go func() {
		<-timer2.C
		fmt.Println("Timer 2 expired")
	}()

	stop2 := timer2.Stop()
	if stop2 {
		fmt.Println("Timer2 Stopped")
	}

	// The first timer will expire ~2s after we start the program,
	// but the second should be stopped before it has a chance to expire.

}