Add nullability changes in core/reactive package

#3762

Signed-off-by: Soby Chacko <[email protected]>

Author: sobychacko

spring-kafka/src/main/java/org/springframework/kafka/core/reactive/ReactiveKafkaConsumerTemplate.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2024 the original author or authors.
+ * Copyright 2019-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -131,20 +131,23 @@ public Flux<String> subscription() {
 		return subscriptions.flatMapIterable(Function.identity());
 	}
 
+	@SuppressWarnings("NullAway") // Lambda
 	public Mono<Void> seek(TopicPartition partition, long offset) {
 		return doOnConsumer(consumer -> {
 			consumer.seek(partition, offset);
 			return null;
 		});
 	}
 
+	@SuppressWarnings("NullAway") // Lambda
 	public Mono<Void> seekToBeginning(TopicPartition... partitions) {
 		return doOnConsumer(consumer -> {
 			consumer.seekToBeginning(Arrays.asList(partitions));
 			return null;
 		});
 	}
 
+	@SuppressWarnings("NullAway") // Lambda
 	public Mono<Void> seekToEnd(TopicPartition... partitions) {
 		return doOnConsumer(consumer -> {
 			consumer.seekToEnd(Arrays.asList(partitions));
@@ -170,13 +173,15 @@ public Flux<TopicPartition> paused() {
 		return paused.flatMapIterable(Function.identity());
 	}
 
+	@SuppressWarnings("NullAway") // Lambda
 	public Mono<Void> pause(TopicPartition... partitions) {
 		return doOnConsumer(c -> {
 			c.pause(Arrays.asList(partitions));
 			return null;
 		});
 	}
 
+	@SuppressWarnings("NullAway") // Lambda
 	public Mono<Void> resume(TopicPartition... partitions) {
 		return doOnConsumer(c -> {
 			c.resume(Arrays.asList(partitions));