Correctly guard against NotYetConnectedExceptions when handling RDHUP.

Motivation:

Commit 2c1f17faa268b9a1b8ef8f1ddaf832d1397719a3 introduced a regression which could cause NotYetConnectedExceptions when handling RDHUP events.

Modifications:

Correct ignore NotYetConnectedException when handling RDHUP events.

Result:

No more regression.

transport-native-epoll/src/main/java/io/netty/channel/epoll/AbstractEpollChannel.java

@@ -33,6 +33,7 @@ import io.netty.util.ReferenceCountUtil;
 import java.io.IOException;
 import java.net.InetSocketAddress;
 import java.nio.ByteBuffer;
+import java.nio.channels.NotYetConnectedException;
 import java.nio.channels.UnresolvedAddressException;
 
 import static io.netty.util.internal.ObjectUtil.checkNotNull;
@@ -348,19 +349,29 @@ abstract class AbstractEpollChannel extends AbstractChannel implements UnixChann
                     try {
                         fd().shutdown(true, false);
                         clearEpollIn0();
-                        pipeline().fireUserEventTriggered(ChannelInputShutdownEvent.INSTANCE);
                     } catch (IOException ignored) {
                         // We attempted to shutdown and failed, which means the input has already effectively been
                         // shutdown.
-                        pipeline().fireUserEventTriggered(ChannelInputShutdownEvent.INSTANCE);
+                        fireEventAndClose(ChannelInputShutdownEvent.INSTANCE);
-                        close(voidPromise());
+                        return;
+                    } catch (NotYetConnectedException ignore) {
+                        // We attempted to shutdown and failed, which means the input has already effectively been
+                        // shutdown.
+                        fireEventAndClose(ChannelInputShutdownEvent.INSTANCE);
+                        return;
                     }
+                    pipeline().fireUserEventTriggered(ChannelInputShutdownEvent.INSTANCE);
                 } else {
                     close(voidPromise());
                 }
             }
         }
 
+        private void fireEventAndClose(Object evt) {
+            pipeline().fireUserEventTriggered(evt);
+            close(voidPromise());
+        }
+
         @Override
         protected void flush0() {
             // Flush immediately only when there's no pending flush.