Optimize Flux pipeline in ClientHttpRequest

spring-web/src/main/java/org/springframework/http/client/reactive/AbstractClientHttpRequest.java

@@ -22,6 +22,7 @@ import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Supplier;
 import java.util.stream.Collectors;
 
+import org.reactivestreams.Publisher;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
@@ -57,7 +58,7 @@ public abstract class AbstractClientHttpRequest implements ClientHttpRequest {
 
 	private final AtomicReference<State> state = new AtomicReference<>(State.NEW);
 
-	private final List<Supplier<? extends Mono<Void>>> commitActions = new ArrayList<>(4);
+	private final List<Supplier<? extends Publisher<Void>>> commitActions = new ArrayList<>(4);
 
 
 	public AbstractClientHttpRequest() {
@@ -112,7 +113,7 @@ public abstract class AbstractClientHttpRequest implements ClientHttpRequest {
 	 * @param writeAction the action to write the request body (may be {@code null})
 	 * @return a completion publisher
 	 */
-	protected Mono<Void> doCommit(@Nullable Supplier<? extends Mono<Void>> writeAction) {
+	protected Mono<Void> doCommit(@Nullable Supplier<? extends Publisher<Void>> writeAction) {
 		if (!this.state.compareAndSet(State.NEW, State.COMMITTING)) {
 			return Mono.empty();
 		}
@@ -128,10 +129,10 @@ public abstract class AbstractClientHttpRequest implements ClientHttpRequest {
 			this.commitActions.add(writeAction);
 		}
 
-		List<? extends Mono<Void>> actions = this.commitActions.stream()
+		List<? extends Publisher<Void>> actions = this.commitActions.stream()
 				.map(Supplier::get).collect(Collectors.toList());
 
-		return Flux.concat(actions).next();
+		return Mono.fromDirect(Flux.concat(actions));
 	}