== sanity-zero test 3a: truncate to a ZEROSTART boundary with an empty prev component ========================================================== 14:23:17 (1790706197) 1+0 records in 1+0 records out 1048576 bytes (1.0 MB, 1.0 MiB) copied, 0.133333 s, 7.9 MB/s 1+0 records in 1+0 records out 1048576 bytes (1.0 MB, 1.0 MiB) copied, 0.122133 s, 8.6 MB/s