the concurrency of chrome to the same server port is 6. You, this for loop, send several requests at the same time. From the figure, there are more than 13 affirmations. The first six are not returned, and the subsequent requests cannot be sent. That's why I know [1 code > 1], [2 code > / p > [2, 2, 2, 2, 2], [3, 3, 3, 3, and 3].