/**
  * @param Command $command
  *
  * @return mixed
  */
 public function handle(Command $command)
 {
     $payload = $command->payload();
     if ($payload instanceof ChangeUserPasswordCommand) {
         $this->handleChangeUserPassword($payload);
     }
 }
 /**
  * @param Command $command
  *
  * @return mixed
  */
 public function handle(Command $command)
 {
     $payload = $command->payload();
     if ($payload instanceof RegisterUserCommand) {
         $this->handleRegisterUser($payload);
     }
 }
 /**
  * @param Command $command
  *
  * @return mixed
  */
 public function handle(Command $command)
 {
     $payload = $command->payload();
     if ($payload instanceof ChangeUsernameCommand) {
         $this->handleUsernameChange($payload);
     }
 }