witness[overlong-slash]: convchr ret=0 consumed=2 oleft=14 out=00 2f aa aa
witness[overlong-4b]: convchr ret=0 consumed=4 oleft=12 out=db ff df ff
witness[lowsur]: convchr ret=0 consumed=2 oleft=13 out=ed b0 80 aa
witness[highsur-lone]: convchr ret=-1 consumed=0 oleft=16 out=aa aa aa aa
witness[valid-slash]: convchr ret=0 consumed=1 oleft=14 out=00 2f aa aa
witness[valid-pair]: convchr ret=0 consumed=4 oleft=12 out=f0 9f 99 88