如何在Google App Engine上执行异步操作？

pip install aiohttp

import asyncio
import aiohttp

async def fetch(url):
    async with aiohttp.ClientSession() as session:
        async with session.get(url) as response:
            return await response.text()

async def main():
    url = 'https://www.example.com'
    response = await fetch(url)
    print(response)

loop = asyncio.get_event_loop()
loop.run_until_complete(main())

import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;

public class AsyncExample {
    public static void main(String[] args) throws ExecutionException, InterruptedException {
        CompletableFuture<String> future = CompletableFuture.supplyAsync(() -> {
            try {
                Thread.sleep(3000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            return "Hello, World!";
        });

        System.out.println("Doing something else...");
        String result = future.get();
        System.out.println(result);
    }
}

package main

import (
	"fmt"
	"time"
)

func asyncFunction() string {
	time.Sleep(3 * time.Second)
	return "Hello, World!"
}

func main() {
	fmt.Println("Doing something else...")

	channel := make(chan string)
	go func() {
		channel <- asyncFunction()
	}()

	result := <-channel
	fmt.Println(result)
}