Add an interface to access individual queues on the switch

net/quic/test_tools/simulator/switch.h

Index: net/quic/test_tools/simulator/switch.h
diff --git a/net/quic/test_tools/simulator/switch.h b/net/quic/test_tools/simulator/switch.h
index 29d42dc64b2de7f3d29de3656b39afa2bff6bd37..c6177c5e41499cc81b0ad947a8582b91c32d3035 100644
--- a/net/quic/test_tools/simulator/switch.h
+++ b/net/quic/test_tools/simulator/switch.h
@@ -31,6 +31,10 @@ class Switch {
     return &ports_[port_number - 1];
   }
 
+  inline const Queue* port_queue(SwitchPortNumber port_number) {
+    return ports_[port_number - 1].queue();
+  }
+
  private:
   class Port : public Endpoint, public UnconstrainedPortInterface {
    public:
@@ -52,7 +56,8 @@ class Switch {
 
     void Act() override;
 
-    inline bool connected() { return connected_; }
+    inline bool connected() const { return connected_; }
+    inline const Queue* queue() const { return &queue_; }
 
    private:
     Switch* parent_;