The United States (US) crackdown on Huawei has made the Chinese telecommunications giant the flashpoint in a monumental economic and technological showdown between the two superpowers that is testing allies of both.One day after the US moved to block Huawei from the US market and banned the export of US technology and materials to the company, China warned Washington on Thursday against further harming trade ties.At the same time, Beijing formally arrested two Canadians who have been detained