+> [Checker] There remains 0 actors, but none to interleave (depth 8).
+> [Checker] Execution came to an end at 1;1;2;1;2;2;0 (state: 17, depth: 7)
+> [Checker] Backtracking from 1;1;2;1;2;2;0
+> [Checker] DFS exploration ended. 17 unique states visited; 2 backtracks (22 transition replays, 2 states visited overall)