linux
export RUSTUP_DIST_SERVER='https://mirrors.ustc.edu.cn/rust-static'
export RUSTUP_UPDATE_ROOT='https://mirrors.ustc.edu.cn/rust-static/rustup'
win32
$ENV:RUSTUP_DIST_SERVER='https://mirrors.ustc.edu.cn/rust-static'
$ENV:RUSTUP_UPDATE_ROOT='https://mirrors.ustc.edu.cn/rust-static/rustup'