Fix reactor-core 3.0.0.RELEASE

Fix the build to work with reactor-core-3.0.0.RELEASE

Author: Rob Winch

spring-web/src/main/java/org/springframework/http/server/reactive/ChannelSendOperator.java

@@ -21,7 +21,6 @@
 import org.reactivestreams.Subscriber;
 import org.reactivestreams.Subscription;
 import reactor.core.publisher.MonoSource;
-import reactor.core.publisher.OperatorAdapter;
 import reactor.core.publisher.Operators;
 
 import org.springframework.util.Assert;
@@ -54,7 +53,7 @@ public void subscribe(Subscriber<? super Void> s) {
 		source.subscribe(new WriteWithBarrier(s));
 	}
 
-	private class WriteWithBarrier extends OperatorAdapter<T, Void> implements Publisher<T> {
+	private class WriteWithBarrier extends Operators.SubscriberAdapter<T, Void> implements Publisher<T> {
 
 		/**
 		 * We've at at least one emission, we've called the write function, the write

spring-web/src/test/java/org/springframework/http/server/reactive/ChannelSendOperatorTests.java

@@ -29,7 +29,7 @@
 import org.reactivestreams.Subscription;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
-import reactor.core.publisher.OperatorAdapter;
+import reactor.core.publisher.Operators;
 import reactor.core.publisher.Signal;
 
 import static org.junit.Assert.assertEquals;
@@ -148,7 +148,7 @@ public Publisher<Void> send(Publisher<String> publisher) {
 			};
 		}
 
-		private class WriteSubscriber extends OperatorAdapter<String, Void> {
+		private class WriteSubscriber extends Operators.SubscriberAdapter<String, Void> {
 
 			public WriteSubscriber(Subscriber<? super Void> subscriber) {
 				super(subscriber);