src/SendPulseApi.php
public function smtpSendMail( $email ) {
        if( empty( $email ) ) {
            return $this->handleError( 'Empty email data' );
        }

        $email['html'] = base64_encode( $email['html'] );
        $data = array(
            'email' => serialize( $email )
        );

        $requestResult = $this->sendRequest( 'smtp/emails', 'POST', $data );

        return $this->handleResult( $requestResult );
    }
public function smtpSendMail( $email ) {
        if( empty( $email ) ) {
            return $this->handleError( 'Empty email data' );
        }

        $email['html'] = base64_encode( $email['html'] );
        $data = array(
            'email' => serialize( $email )
        );

        $requestResult = $this->sendRequest( 'smtp/emails', 'POST', $data );

        return $this->handleResult( $requestResult );
    }
SMTP: send mail

@param $email
@return mixed|stdClass