Macro set_dir 

macro_rules! set_dir {
    () => { ... };
    ($path: literal) => { ... };
}

Set the directory where the storage files are located on non-wasm targets.

fn main(){
    // set the directory to the default location
    set_dir!();
    // set the directory to a custom location
    set_dir!(PathBuf::from("path/to/dir"));
}