There's probably someone who posts this comment every time this article comes up, but:

    #![feature(test)]
    
    extern crate regex;
    extern crate test;
    
    use regex::Regex;
    
    pub fn check(pattern: &Regex, input: &str) -> bool {
        pattern.is_match(input)
    }
    
    #[cfg(test)]
    mod tests {
        use super::*;
        use test::Bencher;
    
        #[bench]
        fn bench_check(b: &mut Bencher) {
            let n = 29;
            let pattern = Regex::new(&format!("{}{}", "a?".repeat(n), "a".repeat(n))).unwrap();
            let input = "a".repeat(n);
            b.iter(|| check(&pattern, &input));
        }
    }

And then:

    $ cat rust-toolchain
    nightly-2018-02-09
    $ cargo bench
       Compiling void v1.0.2
       Compiling lazy_static v1.0.0
       Compiling regex-syntax v0.4.2
       Compiling libc v0.2.36
       Compiling utf8-ranges v1.0.0
       Compiling unreachable v1.0.0
       Compiling thread_local v0.3.5
       Compiling memchr v2.0.1
       Compiling aho-corasick v0.6.4
       Compiling regex v0.2.6
       Compiling regexps v0.1.0 (file:///home/twic/Code/Regexps)
        Finished release [optimized] target(s) in 20.11 secs
         Running target/release/deps/regexps-9c084e63d7d31ac3
    
    running 1 test
    test tests::bench_check ... bench:         212 ns/iter (+/- 8)
    
    test result: ok. 0 passed; 0 failed; 0 ignored; 1 measured; 0 filtered out

Rust's standard regex library isn't the fastest in the world, and the lack of backtracking can be limiting, but it is highly optimised for Rust's main use case of posting showoff comments on Hacker News.

I also tried this in Java (OpenJDK 1.8.0_161-b14), and it took about 24 seconds per iteration at 29 characters.