public function validation()
    {
        $validator = new Validation();

        $validator->add(
            'email',
            new Uniqueness(
                [
                    'message' => 'The customer email must be unique',
                ]
            )
        );

        return $this->validate($validator);
    }

        $count = 100;
        for ($i = 0; $i <= $count; $i++) {
            $before = microtime(true);

            $user = new Users([
                'firstname' => 'John',
                'lastname' => 'Doe',
                'password' => 'securepassword',
                'is_active' => true,
            ]);

        $user->create();

            $after = microtime(true);

            echo sprintf(
                'Took %s seconds. Used %s memory',
                round($after - $before, 4),
                round(((memory_get_usage() / 1024) / 1024), 4) . 'M'
            ) . PHP_EOL;
        }

Took 0.0199 seconds. Used 1.6799M memory
Took 0.0182 seconds. Used 1.6803M memory
Took 0.0185 seconds. Used 1.6806M memory
Took 0.0182 seconds. Used 1.681M memory
...
Took 0.0179 seconds. Used 1.7147M memory
Took 0.0181 seconds. Used 1.715M memory
Took 0.0181 seconds. Used 1.7154M memory
Took 0.0185 seconds. Used 1.7158M memory
Took 0.0181 seconds. Used 1.7161M memory
Took 0.0187 seconds. Used 1.7165M memory