致命错误：从zip包安装SendGrid时找不到类'Guzzle \ Http \ Client'

Question

我正在尝试在我的项目中不使用composer安装SendGrid，只是直接从SendGrid PHP项目zip包中安装，就像他们在这里说的那样：https://github.com/sendgrid/sendgrid-php

所以我解压缩了文件夹sendgrid-php.zip并将此文件夹放在lib文件夹中。 文件夹结构如下所示：

然后我调用库

require("lib/sendgrid-php/sendgrid-php.php");

我的php脚本中也有这个：

$sendgrid = new SendGrid(SENDGRID_API_KEY);
    $email = new SendGrid\Email();
    $email
        ->addTo($to[0]['email'])
        ->setHtml($body)
        ->setSubject($subject)
        ->setFrom($options['from']['email'] )
        ->setFromName( $options['from']['name'] )
        ->setCategories($options['tags']);

    try {
        $sendgrid->send($email);
        echo "send: " . $subject . "\n";
    } catch(\SendGrid\Exception $e) {
        echo $e->getCode();
        foreach($e->getErrors() as $er) {
            echo $er;
        }
    }

当我运行项目时，我收到以下错误：

PHP Fatal error:  Class 'Guzzle\Http\Client' not found in /private/var/www/job/lib/sendgrid-php/lib/SendGrid.php on line 85

Fatal error: Class 'Guzzle\Http\Client' not found in /private/var/www/job/lib/sendgrid-php/lib/SendGrid.php on line 85

无法弄清楚为什么我收到此错误，Guzzle Http Client类实际上在sendgrid-php文件夹中：