feat: the status bar and the exit dump report resequencing, holes and stale packets

src/model.hpp

@@ -195,6 +195,21 @@ struct StreamStats {
   std::atomic<bool> have_config{false};
   std::atomic<std::uint64_t> holes{0};       ///< reserved invalidated spans
   std::atomic<std::uint64_t> hole_slots{0};  ///< stored slots those spans cover
+  /// Out-of-order packets put back in order inside the reorder window: no hole was ever
+  /// seen for these.
+  std::atomic<std::uint64_t> resequenced{0};
+  /// Out-of-order packets delivered behind the sequence, past the window.
+  std::atomic<std::uint64_t> late{0};
+  /// Packets the client still refused outright (a duplicate, or any late packet while
+  /// resequencing is disabled). Counted since the beginning and displayed nowhere until
+  /// now, which is why an inversion had to be inferred from `packets` and `frames`
+  /// diverging.
+  std::atomic<std::uint64_t> stale{0};
+  /// Stored slots a late packet repaired. Declared here rather than with the backfill that
+  /// writes it, because the display segment below is built once and reads it from the start:
+  /// a reading of 0 beside a non-zero `holes` is exactly the honest answer until the
+  /// backfill lands.
+  std::atomic<std::uint64_t> backfilled{0};
 };
 
 /// What the plot is showing, which is one decision made once per frame: the bind, the