== sanity-zero test 3a: truncate to a ZEROSTART boundary with an empty prev component ========================================================== 14:25:48 (1790706348) 1+0 records in 1+0 records out 1048576 bytes (1.0 MB, 1.0 MiB) copied, 0.138731 s, 7.6 MB/s 1+0 records in 1+0 records out 1048576 bytes (1.0 MB, 1.0 MiB) copied, 0.167831 s, 6.2 MB/s