> If you're interested in what actually gets executed (if you're trying to optimize for performance, say), then the `for` loop is clearly explicit than the abstract counterparts.

In what language? GCC will happily not just optimize away your counter variable but perhaps even replace your whole loop with an SIMD operation; I suspect the Go compiler will do the same.

Also, if you're trying to optimize for performance then looking at what code gets executed is (to first order) useless; the dominant factor is cache efficiency and you can't see cache hits/misses by reading the code.