input      packed with trailing  
           network (BE) length   

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