你如何在Cupy中同时运行两个流?在下面的代码中,我想同时执行两个asnumpy操作,每个操作将父级数组的一半,registered_image_list转换为numpy数组 . 目前,流顺序运行,并且在计算时间方面没有增益 . 如何修改代码以使流并发运行?

import cupy as cp
import time
total_frames = 30

parent_list = cp.ndarray(shape=(total_frames,1080,1920,3))
list1 = parent_list[0:15,...]
list2 = parent_list[15:30,...]

stream1 = cp.cuda.stream.Stream()
stream2 = cp.cuda.stream.Stream()
stream1.synchronize()
stream2.synchronize()

start= time.time()
stream1.use()
registered_image_list1 = cp.asnumpy(list1)
stream2.use()
registered_image_list2 = cp.asnumpy(list2)

print(time.time()-start)