Add Connection.isConnected()Z API.

Idea from kamcio96 in #1693

api/src/main/java/net/md_5/bungee/api/connection/Connection.java

@@ -51,6 +51,14 @@ public interface Connection
      */
     void disconnect(BaseComponent reason);
 
+    /**
+     * Gets whether this connection is currently open, ie: not disconnected, and
+     * able to send / receive data.
+     *
+     * @return current connection status
+     */
+    boolean isConnected();
+
     /**
      * Get the unsafe methods of this class.
      *

proxy/src/main/java/net/md_5/bungee/ServerConnection.java

@@ -77,6 +77,12 @@ public class ServerConnection implements Server
         return getInfo().getAddress();
     }
 
+    @Override
+    public boolean isConnected()
+    {
+        return !ch.isClosed();
+    }
+
     @Override
     public Unsafe unsafe()
     {

proxy/src/main/java/net/md_5/bungee/UserConnection.java

@@ -274,9 +274,7 @@ public final class UserConnection implements ProxiedPlayer
                     {
                         sendMessage( bungee.getTranslation( "fallback_lobby" ) );
                         connect( def, null, false );
-                    } else
-                    {
-                        if ( dimensionChange )
+                    } else if ( dimensionChange )
                     {
                         disconnect( bungee.getTranslation( "fallback_kick", future.cause().getClass().getName() ) );
                     } else
@@ -285,7 +283,6 @@ public final class UserConnection implements ProxiedPlayer
                     }
                 }
             }
-            }
         };
         Bootstrap b = new Bootstrap()
                 .channel( PipelineUtils.getChannel() )
@@ -592,4 +589,10 @@ public final class UserConnection implements ProxiedPlayer
             ch.setCompressionThreshold( compressionThreshold );
         }
     }
+
+    @Override
+    public boolean isConnected()
+    {
+        return !ch.isClosed();
+    }
 }

proxy/src/main/java/net/md_5/bungee/connection/InitialHandler.java

@@ -606,4 +606,10 @@ public class InitialHandler extends PacketHandler implements PendingConnection
     {
         return "[" + ( ( getName() != null ) ? getName() : getAddress() ) + "] <-> InitialHandler";
     }
+
+    @Override
+    public boolean isConnected()
+    {
+        return !ch.isClosed();
+    }
 }