How to make a class that inherits the same methods as IO::Path?

Question

I want to build a class in Raku. Here's what I have so far:

unit class Vimwiki::File;

has Str:D $.path is required where *.IO.e;

method size {
    return $.file.IO.s;
}

I'd like to get rid of the size method by simply making my class inherit the methods from IO::Path but I'm at a bit of a loss for how to accomplish this. Trying is IO::Path throws errors when I try to create a new object:

$vwf = Vimwiki::File.new(path => 't/test_file.md');

Must specify a non-empty string as a path
  in block <unit> at t/01-basic.rakutest line 24