Function compare_field_bytes 

pub fn compare_field_bytes(
    a_buf: &[u8],
    a_range: (usize, usize),
    b_buf: &[u8],
    b_range: (usize, usize),
) -> Ordering

Compare two MessagePack values by their decoded content.

Comparison order:

1. Null < Bool < Number < Instant < String < Binary < Array < Map < Ext
2. Within numbers: exact numeric order; integers (uint64 included) never round through f64, an integer against a float compares exactly, and NaN sorts above every number and equals NaN
3. Within instants: by kind (UTC before naive), then signed epoch micros
4. Within strings: lexicographic on raw bytes (valid UTF-8 guarantees byte order = Unicode code-point order for ASCII/Latin-1)
5. Fallback: raw byte comparison