pub fn splice_word_at_bit(words: &mut [u64], bit_offset: usize, word: u64)Expand description
Splice a packed word w (whose bits above the highest valid bit are zero) into
words at the given bit position.
The destination word at bit_offset / 64 is OR’d, preserving any bits below
bit_offset % 64. When w has high bits that spill into the next word, those
bits are assigned (not OR’d) — so callers must ensure that next slot is zero
(e.g. via BufferMut::zeroed).
words.len() need only cover the slots w actually writes to: skipping the
spillover when its bits are all zero means a tail that fits entirely in the
leading word never touches words[dest_word + 1].