Improve error handling

src/CommandBusClient.php

@@ -121,6 +121,18 @@ class CommandBusClient implements CommandBusInterface
                 $data = (array)($message->getData()['data']??[]);
                 $this->emit(self::EVENT_NOTIFY, [ $event, $data ]);
                 break;
+            case Message::MSGTYPE_ERROR: // error
+                $uuid = $message->getUuid();
+                $error = $message->getData()['error'];
+                if ($uuid === "") {
+                    $this->emit('error', [ $error ]);
+                } else {
+                    if (array_key_exists($uuid, $this->pending)) {
+                        $this->pending[$uuid]->reject(new \Exception($error));
+                        unset($this->pending[$uuid]);
+                    }                    
+                }
+                break;
             default:
                 $this->connection->end('{"msg":"error","data":{"error":"Unexpected message type"}}');
         }

src/Message.php

@@ -63,7 +63,7 @@ class Message implements JsonSerializable
         if (!$json || empty($json['msg'])) {
             throw new MessageException("Invalid data");
         }
-        return new Message($json['msg'], $json['data'], $json['uuid']);
+        return new Message($json['msg'], $json['data'], $json['uuid']??"");
     }
 
     public function asResult($result): Message