Yu Hexin of China reacts after men's 50m freestyle final of swimming at the 18th Asian Games in Jakarta, Indonesia, Aug. 21, 2018. Yu won the gold medal. (Xinhua/Fei Maohua)

Yu Hexin (L)of China talks with another contestant after men's 50m freestyle final of swimming at the 18th Asian Games in Jakarta, Indonesia, Aug. 21, 2018. Yu won the gold medal. (Xinhua/Ding Ting)

Yu Hexin of China enters water as he competes men's 50m freestyle final of swimming at the 18th Asian Games in Jakarta, Indonesia, Aug. 21, 2018. Yu won the gold medal. (Xinhua/Ding Ting)

Yu Hexin of China reacts after men's 50m freestyle final of swimming at the 18th Asian Games in Jakarta, Indonesia, Aug. 21, 2018. Yu won the gold medal. (Xinhua/Fei Maohua)

Yu Hexin of China reacts after men's 50m freestyle final of swimming at the 18th Asian Games in Jakarta, Indonesia, Aug. 21, 2018. Yu won the gold medal. (Xinhua/Fei Maohua)

Yu Hexin of China reacts after men's 50m freestyle final of swimming at the 18th Asian Games in Jakarta, Indonesia, Aug. 21, 2018. Yu won the gold medal. (Xinhua/Li Xiang)