问Golang通道维护

EN

package main

import (
    "fmt"
    "time"
)

func main() {
    queue := make(chan int, 1)
    defer close(queue)

    // Fire up a consumer.
    // Ensure it times out after 3 seconds of waiting for a value.
    go func() {
        select {
        case val := <-queue:
            fmt.Printf("Received: %d\n", val)
        case <-time.After(3 * time.Second):
            fmt.Println("Timeout!")
        }
    }()

    // Do something important for 5 seconds.
    <-time.After(5 * time.Second)

    // Send value to user.
    queue <- 123
}