[root@dfbsd ~]# /tmp/mirror_poc /mnt/f1 nodata
issuing HAMMERIOC_MIRROR_WRITE mode=nodata size=80...
MIRROR_WRITE rc=0 head.error=0 head.flags=00000000 count=80
=> stream processed
[root@dfbsd ~]# /tmp/mirror_poc /mnt/f1 readback
MIRROR_READ rc=0 error=0 count=664
  mrec[0] sig=4dd97272 type=00000001 rec_size=80 obj=1234 key=100 ctid=1000 dtid=0 btype=52 rt=0012 loc=00000000 dlen=0
  mrec[80] sig=4dd97272 type=00000001 rec_size=208 obj=1 key=0 ctid=100000001 dtid=0 btype=52 rt=0001 loc=00000001 dlen=128
  mrec[288] sig=4dd97272 type=00000001 rec_size=372 obj=1 key=0 ctid=100000001 dtid=0 btype=52 rt=0015 loc=00000002 dlen=292
=> the NODATA-flagged record (obj=1234) WAS installed with dlen=0: the
   case HAMMER_MREC_TYPE_REC_NODATA skip path never ran (dead case).