import time
import threading

def application(environ, start_response):
    delay = float(environ.get('HTTP_X_DELAY', 0))

    time.sleep(delay)

    start_response('200', [
        ('Content-Length', '0'),
        ('Wsgi-Multithread', str(environ['wsgi.multithread'])),
        ('X-Thread', str(threading.currentThread().ident))
    ])

    return []