下面的代碼：// Sample program to show how to use the WithDeadline function// of the Context package.package mainimport (    "context"    "fmt"    "time")type data struct {    UserID string}func main() {    // Set a duration.    // duration := 150 * time.Millisecond    duration := time.Now().Add(3 * time.Second)    // Create a context that is both manually cancellable and will signal    // a cancel at the specified duration.    ctx, cancel := context.WithDeadline(context.Background(), duration)    defer cancel()    // Create a channel to received a signal that work is done.    ch := make(chan data, 1)    // Ask the goroutine to do some work for us.    go func() {        // Simulate work.        time.Sleep(50 * time.Millisecond)        // Report the work is done.        ch <- data{"123"}    }()    // Wait for the work to finish. If it takes too long move on.    select {    case d := <-ch:        fmt.Println("work complete", d)    case <-ctx.Done():        fmt.Println("work cancelled")    }}用于WithDeadline發送 timer'd cancel()。這可以使用以下方法完成：duration := 150 * time.Millisecond// Create a context that is both manually cancellable and will signal// a cancel at the specified duration.ctx, cancel := context.WithTimeout(context.Background(), duration)在內部，context.WithTimeout調用該context.WithDeadline函數并通過將超時添加到當前時間來生成截止日期。有多么context.WithTimeout()不同context.WithDeadline()