异步调用python在下一个请求之前等待命令完成

Question

我已经编写了下面提到的代码，但是我希望该过程在开始下一批之前不要等待命令完成。这段代码正在休眠18秒。

import urllib.request
import subprocess
import time
import os


URLS = [ 'sleep 10','sleep 18','echo hi'] * 10
#stdout=subprocess.DEVNULL,
def load_url(url, timeout):
    FNULL = open(os.devnull, 'w')
    result = subprocess.call(url, shell=True, stdout=subprocess.DEVNULL,stderr=subprocess.DEVNULL)

count = 0
x= True
starttime = time.time()
while True:
    count = count + 5
    print ("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx")
    #time.sleep(2)
    with concurrent.futures.ThreadPoolExecutor(max_workers=100) as executor:
        future_to_url = {executor.submit(load_url, url, 0): url for url in URLS}
        for future in concurrent.futures.as_completed(future_to_url):
            url = future_to_url[future]
            try:
                data = future.result()
                pass
            except Exception as exc:
                pass
            else:
                pass