[ISSUE #3949] improve readability.

proxy/src/main/java/org/apache/rocketmq/proxy/processor/DefaultMessagingProcessor.java

@@ -217,7 +217,7 @@ public class DefaultMessagingProcessor extends AbstractStartAndShutdown implemen
 
     @Override
     public ProxyRelayService getProxyOutService() {
-        return this.serviceManager.getProxyOutService();
+        return this.serviceManager.getProxyRelayService();
     }
 
 }

proxy/src/main/java/org/apache/rocketmq/proxy/service/ClusterServiceManager.java

@@ -122,7 +122,7 @@ public class ClusterServiceManager extends AbstractStartAndShutdown implements S
     }
 
     @Override
-    public ProxyRelayService getProxyOutService() {
+    public ProxyRelayService getProxyRelayService() {
         return this.proxyRelayService;
     }
 

proxy/src/main/java/org/apache/rocketmq/proxy/service/LocalServiceManager.java

@@ -78,7 +78,7 @@ public class LocalServiceManager extends AbstractStartAndShutdown implements Ser
     }
 
     @Override
-    public ProxyRelayService getProxyOutService() {
+    public ProxyRelayService getProxyRelayService() {
         return this.proxyRelayService;
     }
 

proxy/src/main/java/org/apache/rocketmq/proxy/service/ServiceManager.java

@@ -35,5 +35,5 @@ public interface ServiceManager extends StartAndShutdown {
 
     TransactionService getTransactionService();
 
-    ProxyRelayService getProxyOutService();
+    ProxyRelayService getProxyRelayService();
 }

proxy/src/test/java/org/apache/rocketmq/proxy/processor/BaseProcessorTest.java

@@ -78,7 +78,7 @@ public class BaseProcessorTest extends InitConfigAndLoggerTest {
         when(serviceManager.getProducerManager()).thenReturn(producerManager);
         when(serviceManager.getConsumerManager()).thenReturn(consumerManager);
         when(serviceManager.getTransactionService()).thenReturn(transactionService);
-        when(serviceManager.getProxyOutService()).thenReturn(proxyRelayService);
+        when(serviceManager.getProxyRelayService()).thenReturn(proxyRelayService);
     }
 
     protected static ProxyContext createContext() {