fix SessionPushed handling

lib/floof.ex

@@ -98,6 +98,10 @@ defmodule Floof do
           :ok = send_summary(client, :requestpull, Floof.SessionManager.peek(sesskey))
           {backlog, sesskey}
 
+        {:SessionPushed, sesskey, dcdhash} ->
+          :ok = send_summary(client, :requestpull, [dcdhash])
+          {backlog, sesskey}
+
         {:SessionDetached, old_sesskey} ->
           sesskey2 =
             if sesskey == old_sesskey do

lib/floof/session_manager.ex

@@ -76,11 +76,11 @@ defmodule Floof.SessionManager do
         )
 
       {:ok, all_keys} = all_session_keys(state)
+      added_dets_ents = for key <- MapSet.difference(all_keys, filter_keys), do: {key, subkey}
 
-      if not Enum.empty?(all_keys) do
+      if not Enum.empty?(added_dets_ents) do
         # only store packets when we have any sessions
         :ok = Floof.PacketSpool.store(subkey, value)
-        added_dets_ents = for key <- MapSet.difference(all_keys, filter_keys), do: {key, subkey}
         :ok = :dets.insert(state.dets_file, added_dets_ents)
       end