多处理 AsyncResult.get() 在 Python 3.7.2 中挂起，但在 3.6 中没有

I'm trying to port some code from Python 3.6 to Python 3.7 on Windows 10. I see the multiprocessing code hang when calling .get() on the AsyncResult object. The code in question is much more complicated, but I've boiled it down to something similar to the following program.

import multiprocessing


def main(num_jobs):
    num_processes = max(multiprocessing.cpu_count() - 1, 1)
    pool = multiprocessing.Pool(num_processes)

    func_args = []
    results = []

    try:
        for num in range(num_jobs):
            args = (1, 2, 3)
            func_args.append(args)
            results.append(pool.apply_async(print, args))

        for result, args in zip(results, func_args):
            print('waiting on', args)
            result.get()
    finally:
        pool.terminate()
        pool.join()


if __name__ == '__main__':
    main(5)

此代码也在 Python 2.7 中运行.出于某种原因，对 get() 的第一次调用在 3.7 中挂起，但在其他版本上一切正常.

import _winapi
import multiprocessing.spawn
multiprocessing.spawn.set_executable(_winapi.GetModuleFileName(0))