difference with clang-format for spaces before parentheses

space before parentheses rules are different, I want no space before empty, space when non-empty.

But in r# it'll always put a space when it's the declaration.

How can I get r# to do the same as clang-format?

clang-format:

    void ftest1 (int a);
    void ftest2 (int a) { a++; }
    void ftest3();

    void ftest4()
    {
        int a;
        ftest3();
        ftest2 (a);
    };
 

r#:

    void ftest1 (int a);
    void ftest2 (int a) { a++; }
    void ftest3 ();

    void ftest4 ()
    {
        int a;
        ftest3();
        ftest2 (a);
    };