crypto/cipher concurrent ctr mode?

[Juan F. Giménez Silva]

Hi, I'm doing a MOOC of cryptography  and as a homework we had to implement CTR Mode decryption/encryption. As I saw in the course CTR can be implemented with concurrency since the IV+1  can be calculated and I did just for fun and to learn a bit about goroutines[0] . When I see the code of ctr in the standard library I see that it's sequential[1] . So I wonder if it would be a significant benefit to implement it with concurrency or if goroutines would make it actually worse in some way. What is the reason for doing it sequentially? is there any relevant benchmark on this?

Thanks!

[0] http://juanfgs.eosweb.info/post/43

[1] https://golang.org/src/crypto/cipher/ctr.go