package main

import (
    "context"
    "fmt"
    "time"
)

func main() {
    ctx, cancel := context.WithCancel(context.Background())

    go func() {
        select {
        case <-ctx.Done():
            fmt.Printf("%v Cancelled \n", time.Now().String())
        case <-time.After(1 * time.Microsecond):
            fmt.Printf("%v Run \n", time.Now().String())
        }
    }()

    fmt.Printf("%v Start\n", time.Now().String())
    time.Sleep(2 * time.Microsecond)

    fmt.Printf("%v Finish\n", time.Now().String())
    cancel()
    time.Sleep(1 * time.Microsecond)

    fmt.Printf("%v Exit\n", time.Now().String())
}