The Uber of China, Didi Chuxing, has officially filed to go public in the US stock market.Analysts peg its valuation to be anywhere between $70 billion to $100 billion, which could spell lucrative returns for its three biggest shareholders — Uber, SoftBank, and Tencent.The company did not specify which exchange it intends to trade on, just that it expects to list under the ticker symbol DIDI.China...