我正在尝试创建一个装饰器，该装饰器将全局验证请求存储桶是否已满。 铲斗尺寸为40，泄漏率为每秒2。 我希望能够在维护bucker sub 40的同时线程化不同请求的多个实例。self.bucket_current怎么可能变为负数？另外，如何调试这些线程及其作用？

from time import sleep
from concurrent.futures import ThreadPoolExecutor
from math import ceil

class Counter:
    def __init__(self):
        self.bucket_size = 40
        self.bucket_current = 0
        self.bucket_leak_rate = 2


    def countdown(self,secs):
        self.bucket_current += secs
        print(self.bucket_current)
        r = ceil(self.bucket_current/self.bucket_leak_rate)
        sleep(1)
        while self.bucket_current > 0:
            for _ in range(1,r+1):
                if self.bucket_current != 1:
                    self.bucket_current -= 2
                else:
                    self.bucket_current -= 1

                print(self.bucket_current)
                sleep(1)


c = Counter()

with ThreadPoolExecutor() as executor:
    executor.submit(c.countdown,9)
    sleep(3)
    executor.submit(c.countdown,7)

输出：

9
7
5
3
10
8
6
4
2
0
-2
-4
-6
-8
-10
-12
-14