Yeah, the point of moving from C to Go would be to get away from all the disasters. But if the core is small enough using short bursts of inline assembly to actually calculate the cipher, while all the complex protocol handling and buffer manipulation is done in the safe layer, it would be a good solution.

Edit: that does indeed appear to be what they've done. In particular using the AESENC instruction. https://github.com/cloudflare/go/blob/master/src/crypto/aes/...