Clear all connections in SessionManager during HomekitRoot.stop() (#55)

Remove all subscriptions during homekitRoot.stop()

This is a potential fix for #54

src/main/java/com/beowulfe/hap/HomekitRoot.java

@@ -126,6 +126,7 @@ public void start() {
   public void stop() {
     advertiser.stop();
     webHandler.stop();
+    subscriptions.removeAll();
     started = false;
   }
 

src/main/java/com/beowulfe/hap/impl/connections/SubscriptionManager.java

@@ -5,6 +5,7 @@
 import com.beowulfe.hap.impl.http.HttpResponse;
 import com.beowulfe.hap.impl.json.EventController;
 import java.util.Collections;
+import java.util.Iterator;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
@@ -77,10 +78,13 @@ public synchronized void removeConnection(HomekitClientConnection connection) {
             subscriptions.get(characteristic);
         characteristicSubscriptions.remove(connection);
         if (characteristicSubscriptions.isEmpty()) {
+          LOGGER.debug("Unsubscribing from characteristic as all subscriptions are closed");
           characteristic.unsubscribe();
+          subscriptions.remove(characteristic);
         }
       }
     }
+    LOGGER.debug("Removed connection {}", connection.hashCode());
   }
 
   private <T> Set<T> newSet() {
@@ -98,4 +102,16 @@ public void publish(int accessoryId, int iid, EventableCharacteristic changed) {
       LOGGER.error("Failed to create new event message", e);
     }
   }
+
+  /** Remove all existing subscriptions */
+  public void removeAll() {
+    LOGGER.debug("Removing {} reverse connections from subscription manager", reverse.size());
+    Iterator<HomekitClientConnection> i = reverse.keySet().iterator();
+    while (i.hasNext()) {
+      HomekitClientConnection connection = i.next();
+      LOGGER.debug("Removing connection {}", connection.hashCode());
+      removeConnection(connection);
+    }
+    LOGGER.debug("Subscription sizes are {} and {}", reverse.size(), subscriptions.size());
+  }
 }