> Have you never had to indicate how many bytes you are sending over a stream...

I have and I generally like the syntax to be more explicit (since I so rarely work in bytes): string.getBytes().length

You make all fair points, and I guess it is my opinion that varies then but I think the rule of least surprise would involve returning the rune count for both strings and string slices. Also, wow, range iterates over runes but len returns byte count. That's messed up.