<?php
use Microsoft\Graph\GraphServiceClient;
use Microsoft\Graph\Generated\Users\Item\CalendarView\Delta\DeltaRequestBuilderGetRequestConfiguration;
$graphServiceClient = new GraphServiceClient($tokenRequestContext, $scopes);
$requestConfiguration = new DeltaRequestBuilderGetRequestConfiguration();
$headers = [
'Prefer' => 'odata.maxpagesize=2',
];
$requestConfiguration->headers = $headers;
$queryParameters = DeltaRequestBuilderGetRequestConfiguration::createQueryParameters();
$queryParameters->startDateTime = "{start_datetime}";
$queryParameters->endDateTime = "{end_datetime}";
$requestConfiguration->queryParameters = $queryParameters;
$result = $graphServiceClient->me()->calendarView()->delta()->get($requestConfiguration)->wait();