> Print to string: (s)printf
> Print to file: (f)printf
> Print to buffer: (isc_buffer_)printf

True, and I did think of that, but my brain tends to look at what's
after the last underscore as the main indicator of what a function
does, so to me isc_buffer_printf() sounds like it should print the
content of a buffer to stdout. However, since I seem to be the only
one with that quirk, I'm fine with the original name.