China's slow post-Covid recovery could be a lasting headwind for its stock market.With the mainland's two largest indexes — the Shanghai Composite and the Shenzhen Composite — each negative so far in 2024, KraneShares Chief Investment Officer Brendan Ahern thinks government stimulus is necessary to kick-start the country's stock market performance."Investors, particularly in mainland China … [are] looking for much, much stronger fiscal support from the government," he told CNBC's "ETF Edge" this week. "Thus ...