Re: writeFile with iterator

[cblake]

Garry: --opt:size (and things like gcc -Os) instructs compilers to choose 
trade-offs to make object code smaller rather than faster. E.g., on Oderwat's 
code, I get 0.19 seconds with just -d:release (with gcc-6.1 on Linux x86_64, 
i7-6700k @4.5GHz). If I additionally specify --opt:size the time rises to 0.28 
seconds, almost 1.5X slower. The program text segment is 80KB in the fast case 
but 33KB in the slow case. So, all is behaving as expected/requested.