abd_zero_off
abd_zero_off(abd, csize, psize - csize);
abd_zero_off(to_write, psize, asize - psize);
abd_zero_off(to_write, size, asize - size);
abd_zero_off(eabd, psize, asize - psize);
void abd_zero_off(abd_t *, size_t, size_t);
abd_zero_off(abd, 0, size);
abd_zero_off(aio->io_abd,
abd_zero_off(dst, size,
abd_zero_off(cdata, psize, rounded - psize);
abd_zero_off(abuf, zio->io_size, asize - zio->io_size);
abd_zero_off(adata, psize, asize - psize);