Use AtomicBoolean for receive ot ignore other messages

The `RabbitAmqpTemplate.receive()` uses an AMQP 1.0 `Consumer`
to receive a single message.
There is a race condition when we have several messages in the queue,
so after receiving one, this consumer may deliver the next one.

* Use `AtomicBoolean messageReceived` to accept only one message from the consumer.
Since the `CompletableFuture` closes that consumer on its completion, there is just small
chance that a new message would be handed to the handler.
And since we do nothing with this new message, it will come back to the queue after we close consumer.

spring-rabbitmq-client/src/main/java/org/springframework/amqp/rabbitmq/client/RabbitAmqpTemplate.java

@@ -20,6 +20,7 @@ import java.time.Duration;
 import java.util.Objects;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.function.Supplier;
@@ -321,6 +322,8 @@ public class RabbitAmqpTemplate implements AsyncAmqpTemplate, DisposableBean {
 	public CompletableFuture<Message> receive(String queueName) {
 		CompletableFuture<Message> messageFuture = new CompletableFuture<>();
 
+		AtomicBoolean messageReceived = new AtomicBoolean();
+
 		Consumer consumer =
 				this.connectionFactory.getConnection()
 						.consumerBuilder()
@@ -328,8 +331,10 @@ public class RabbitAmqpTemplate implements AsyncAmqpTemplate, DisposableBean {
 						.initialCredits(1)
 						.priority(10)
 						.messageHandler((context, message) -> {
-							context.accept();
-							messageFuture.complete(RabbitAmqpUtils.fromAmqpMessage(message, null));
+							if (messageReceived.compareAndSet(false, true)) {
+								context.accept();
+								messageFuture.complete(RabbitAmqpUtils.fromAmqpMessage(message, null));
+							}
 						})
 						.build();