如何在stuctopt定义中访问运行时定义的变量？

[dependencies]
lazy_static = "1.4"
parking_lot = "0.11"

use lazy_static::lazy_static;
use std::sync::Mutex;

lazy_static! {
    static ref RUNTIME_VAR: Mutex<String> = Mutex::new(String::new());
}

#[derive(StructOpt)]
struct MyOptions {
    #[structopt(short = "v", long = "var")]
    var: String,
}

fn main() {
    let options = MyOptions::from_args();

    // 使用闭包访问全局静态变量
    let var = RUNTIME_VAR.lock().unwrap();
    println!("Runtime variable value: {}", *var);
    println!("User defined variable value: {}", options.var);
}