Function std::os::homedir
pub fn homedir() -> Option<Path>
Returns the path to the user's home directory, if known.
On Unix, returns the value of the 'HOME' environment variable if it is set and not equal to the empty string.
On Windows, returns the value of the 'HOME' environment variable if it is set and not equal to the empty string. Otherwise, returns the value of the 'USERPROFILE' environment variable if it is set and not equal to the empty string.
Otherwise, homedir returns option::none.