input      packed with leading  
           network (BE) length   

ACGT       00 00 00 04 1b       
ACGTA      00 00 00 05 1b 00
ACGTAA     00 00 00 06 1b 00   
ACGTAAA    00 00 00 07 1b 00   
ACGTAAAA   00 00 00 08 1b 00   
ACGTAAAAA  00 00 00 09 1b 00