Debounce backfill dashboard updates to once per second

lib/microwaveprop_web/live/backfill_live.ex

@@ -34,7 +34,8 @@ defmodule MicrowavepropWeb.BackfillLive do
        unprocessed: unprocessed,
        db_stats: db_stats,
        last_enqueued: nil,
-       enqueuing: false
+       enqueuing: false,
+       refresh_timer: nil
      )}
   end
 
@@ -59,21 +60,33 @@ defmodule MicrowavepropWeb.BackfillLive do
   end
 
   def handle_info({:contact_status_changed, _data}, socket) do
-    {:noreply,
-     assign(socket,
-       unprocessed: count_unprocessed(),
-       db_stats: fetch_db_stats()
-     )}
+    {:noreply, schedule_refresh(socket)}
   end
 
   def handle_info({:oban_job_changed, _data}, socket) do
+    {:noreply, schedule_refresh(socket)}
+  end
+
+  def handle_info(:refresh_stats, socket) do
     {:noreply,
      assign(socket,
        stats: fetch_stats(),
-       unprocessed: count_unprocessed()
+       unprocessed: count_unprocessed(),
+       db_stats: fetch_db_stats(),
+       refresh_timer: nil
      )}
   end
 
+  defp schedule_refresh(%{assigns: %{refresh_timer: ref}} = socket) when is_reference(ref) do
+    # Already scheduled, skip
+    socket
+  end
+
+  defp schedule_refresh(socket) do
+    ref = Process.send_after(self(), :refresh_stats, 1000)
+    assign(socket, refresh_timer: ref)
+  end
+
   @enrichable [:pending, :failed]
 
   defp enqueue_batch(limit) do