Add Message interfaces for messages

src/Message/Call.php

@@ -6,7 +6,7 @@
 
 use parallel\Channel;
 
-final class Call
+final class Call implements Message
 {
     private Channel $channel;
 

src/Message/Destruct.php

@@ -4,7 +4,7 @@
 
 namespace ReactParallel\ObjectProxy\Message;
 
-final class Destruct
+final class Destruct implements Message
 {
     private string $hash;
     private string $objectHash;

src/Message/Existence.php

@@ -4,7 +4,7 @@
 
 namespace ReactParallel\ObjectProxy\Message;
 
-final class Existence
+final class Existence implements Message
 {
     private string $hash;
     private string $objectHash;

src/Message/Link.php

@@ -4,7 +4,7 @@
 
 namespace ReactParallel\ObjectProxy\Message;
 
-final class Link
+final class Link implements Message
 {
     private string $hash;
     private string $objectHash;

src/Message/Message.php

@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace ReactParallel\ObjectProxy\Message;
+
+interface Message
+{
+    public function hash(): string;
+
+    public function objectHash(): string;
+}

src/Message/Notify.php

@@ -4,7 +4,7 @@
 
 namespace ReactParallel\ObjectProxy\Message;
 
-final class Notify
+final class Notify implements Message
 {
     private string $hash;
     private string $objectHash;