<?php
use Microsoft\Graph\Beta\GraphServiceClient;
use Microsoft\Graph\Beta\Generated\Users\Item\Messages\MessagesRequestBuilderGetRequestConfiguration;
$graphServiceClient = new GraphServiceClient($tokenRequestContext, $scopes);
$requestConfiguration = new MessagesRequestBuilderGetRequestConfiguration();
$headers = [
'Prefer' => 'outlook.body-content-type="text"',
];
$requestConfiguration->headers = $headers;
$queryParameters = MessagesRequestBuilderGetRequestConfiguration::createQueryParameters();
$queryParameters->select = ["subject","body","bodyPreview","uniqueBody"];
$requestConfiguration->queryParameters = $queryParameters;
$result = $graphServiceClient->me()->messages()->get($requestConfiguration)->wait();