Unnecessary AtomicBoolean in inactive token attribute (#1378)

Author: stepancheg

client/src/main/java/org/asynchttpclient/netty/channel/Channels.java

@@ -17,8 +17,6 @@
 import io.netty.util.Attribute;
 import io.netty.util.AttributeKey;
 
-import java.util.concurrent.atomic.AtomicBoolean;
-
 import org.asynchttpclient.netty.DiscardEvent;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -28,7 +26,9 @@ public class Channels {
     private static final Logger LOGGER = LoggerFactory.getLogger(Channels.class);
 
     private static final AttributeKey<Object> DEFAULT_ATTRIBUTE = AttributeKey.valueOf("default");
-    private static final AttributeKey<AtomicBoolean> INACTIVE_TOKEN_ATTRIBUTE = AttributeKey.valueOf("inactiveToken");
+    private static final AttributeKey<Inactive> INACTIVE_TOKEN_ATTRIBUTE = AttributeKey.valueOf("inactiveToken");
+
+    private enum Inactive { INSTANCE }
 
     public static Object getAttribute(Channel channel) {
         Attribute<Object> attr = channel.attr(DEFAULT_ATTRIBUTE);
@@ -48,11 +48,11 @@ public static boolean isChannelValid(Channel channel) {
     }
 
     public static void setInactiveToken(Channel channel) {
-        channel.attr(INACTIVE_TOKEN_ATTRIBUTE).set(new AtomicBoolean(true));
+        channel.attr(INACTIVE_TOKEN_ATTRIBUTE).set(Inactive.INSTANCE);
     }
 
     public static boolean getInactiveToken(Channel channel) {
-        return channel != null && channel.attr(INACTIVE_TOKEN_ATTRIBUTE).get().getAndSet(false);
+        return channel != null && channel.attr(INACTIVE_TOKEN_ATTRIBUTE).getAndSet(null) != null;
     }
 
     public static void silentlyCloseChannel(Channel channel) {