//request contacts from contactfolder with id = contactFolderId
var request = m_graphClient.Me.ContactFolders[contactFolderId].Contacts.Request().Top(1000);
var result = await request.GetAsync();
//add result to a list
contacts.AddRange(result);
//send nextLink request if available
var nextPage = result;
while (nextPage.NextPageRequest != null)
{
    var nextPageRequest = nextPage.NextPageRequest;
    nextPage = await nextPageRequest.GetAsync();
    contacts.AddRange(nextPage);
}

//request events from calendar with id = calendarFolderId
var request = m_graphClient.Me.Calendars[calendarFolderId].Events.Request().Top(1000);
var result = await request.GetAsync();
//add result to a list
events.AddRange(result);
//send nextLink request if available
var nextPage = result;
while (nextPage.NextPageRequest != null)
{
     var nextPageRequest = nextPage.NextPageRequest;
     nextPage = await nextPageRequest.GetAsync();
     events.AddRange(nextPage);
}