[#1710] Add missing duplicate() overrides in interfaces

codec-http/src/main/java/io/netty/handler/codec/http/ComposedLastHttpContent.java

@@ -50,7 +50,7 @@ final class ComposedLastHttpContent implements LastHttpContent {
     }
 
     @Override
-    public HttpContent duplicate() {
+    public LastHttpContent duplicate() {
         return copy();
     }
 

codec-http/src/main/java/io/netty/handler/codec/http/FullHttpMessage.java

@@ -28,4 +28,7 @@ public interface FullHttpMessage extends HttpMessage, LastHttpContent {
 
     @Override
     FullHttpMessage retain();
+
+    @Override
+    FullHttpMessage duplicate();
 }

codec-http/src/main/java/io/netty/handler/codec/http/FullHttpRequest.java

@@ -29,6 +29,9 @@ public interface FullHttpRequest extends HttpRequest, FullHttpMessage {
     @Override
     FullHttpRequest retain();
 
+    @Override
+    FullHttpRequest duplicate();
+
     @Override
     FullHttpRequest setProtocolVersion(HttpVersion version);
 

codec-http/src/main/java/io/netty/handler/codec/http/FullHttpResponse.java

@@ -29,6 +29,9 @@ public interface FullHttpResponse extends HttpResponse, FullHttpMessage {
     @Override
     FullHttpResponse retain();
 
+    @Override
+    FullHttpResponse duplicate();
+
     @Override
     FullHttpResponse setProtocolVersion(HttpVersion version);
 

codec-http/src/main/java/io/netty/handler/codec/http/LastHttpContent.java

@@ -100,4 +100,7 @@ public interface LastHttpContent extends HttpContent {
 
     @Override
     LastHttpContent retain();
+
+    @Override
+    LastHttpContent duplicate();
 }