Reusing a scan's probes costs one stat per file to see that it is as it was. They ran one after another, so on a network share every file waited for a round trip. They now run 16 at a time, in the import's batches and in the scan's check of an earlier scan's probes.
Measured on this version with each stat made to take 2 ms (a stand-in for a share's round trip): 5,990 stats took 15.1 s one at a time and 0.95 s through `stat_all`, with the answers in the same order. An earlier version of this change, tried on a real network share, spent most of the import's time in these stats; that figure is not repeated here because it was not taken on this code.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
