And just like that Problem 10 is done and correct whoohoo 🥳 It was easy because in Problem 7 I'd already written an iterator to produce infinite primes. So the solution for finding the sum of primes under 2,000,000 is basically (shortened):

  primes := iter.take_while(iter.filter(prime_candidates(), is_prime), fn(p) { p < n })
  print(iter.sum(primes))

And of course the answer is: 142913828922 which took ~21.ss for the Go Vm to compuete.