How to set a custom FirefoxDriver profile?

Question

C++ / C#

FirefoxOptions options = new FirefoxOptions();
options.Profile = new FirefoxProfile(path);
FirefoxDriver driver = new FirefoxDriver(options);

That doesn't work.

FirefoxDriver driver = new FirefoxDriver(new FirefoxProfile(path));

So too.
Passing a profile via the -profile argument stops responding to commands. Doesn't work GoToUrlnormal.

FirefoxProfile profile = new FirefoxProfile(path);
FirefoxOptions options = new FirefoxOptions();
options.Profile = profile;
FirefoxDriver driver = new FirefoxDriver(options);

And if you do this, but it will create a default one in the temp directory.
How to be anyway?