Function count_all 

pub fn count_all(data: &[u8]) -> WcCounts

Count everything in a single pass for maximum efficiency. When multiple flags are requested, this avoids re-scanning.

Iterates byte-by-byte for line/word/max-line-length counting, and uses UTF-8 leading byte detection for character counting (a byte is a char start if it’s not a continuation byte 0x80..0xBF).