pub fn md5_x4(msgs: [&[u8]; 4]) -> [[u8; 16]; 4]Expand description
MD5 of FOUR equal-length messages at once — 4-way SSE2 multi-buffer, the high-throughput path for
hashing many same-size records (bulk name-based ids, dedup keys, content addresses). All four ABCD
states advance in one __m128i (lane j = message j), so ~4× a scalar MD5 per message. The four
inputs MUST share a length; returns the four 16-byte digests, byte-identical to md5 per lane.