src/Leevel/Mail/Mail.php
public function attach(string $file, Closure $callbacks = null): IMail
    {
        $this->makeMessage();

        return $this->callbackAttachment(
            $this->createPathAttachment($file),
            $callbacks
        );
    }
public function attach(string $file, Closure $callbacks = null): IMail
    {
        $this->makeMessage();

        return $this->callbackAttachment(
            $this->createPathAttachment($file),
            $callbacks
        );
    }
添加附件.

@param string        $file
@param null|\Closure $callbacks

@return $this