How to notify a handler?

To notify a handler in Go, you can use channels to communicate between goroutines. Here's a simple example demonstrating how to notify a handler when a task is completed:

package main

import (
    "fmt"
    "time"
)

// This function simulates a worker that performs some work.
func worker(done chan bool) {
    fmt.Print("working...")
    time.Sleep(time.Second) // Simulate work with sleep
    fmt.Println("done")

    // Notify that the work is done
    done <- true
}

func main() {
    // Create a channel to notify when the worker is done
    done := make(chan bool, 1)

    // Start the worker goroutine
    go worker(done)

    // Wait for the notification from the worker
    <-done

    // Call the handler after receiving the notification
    handler()
}

// Example handler function
func handler() {
    fmt.Println("Handler notified and executed.")
}

In this example, the worker function performs some work and sends a notification through the done channel when it's finished. The main function waits for this notification before calling the handler function.