回複：If cost is not an issue but time is, you may have a

law firm file the application for you. As far as I know, in about two months after the filing, you will get a case number. From that point, you can leave the US but your case still be treated as if it is from US, which means total processing time can be around 15 months, faster than 4 years in China. One thing, before your application, you need to have been staying in the US for at least over one year.

After you get the case number, in about 4-5 months, you needs to prepare document for second step ( such as bank saving certificate, China degree notarization, etc. ). During the 15 months, you may need to do health check ( okay to do it outside US ).

Before you leave the US, law firm will have you take fingerprint...In the future, Canada will deal with the law firm most of the time so you don't need to keep an valid US address to receive the notice, etc.

Very convenient but you need to pay around 2K for the law firm service. Alternatively, you can find cheaper firm, or even file the case by yourself. In later case, you may need to leave your friends address and have them handle the letter / notice / requirement for you .... Don't know whether that is easy. Hope this helps.