//  reading unread messages with paging
using var client = GraphClient.GetClient(tokenProvider, config.Tenant);

// paging option
var itemsPerPage = 10;
// create unread messages filter
GraphQueryBuilder builder = new GraphQueryBuilder();
builder.IsRead.Equals(false);
var query = builder.GetQuery();
// list messages
var pageInfo = client.ListMessages(KnownFolders.Inbox, new PageInfo(itemsPerPage), query);
var  messages = pageInfo.Items;

while (!pageInfo.LastPage)
{
    pageInfo = client.ListMessages(KnownFolders.Inbox, pageInfo.NextPage, query);
    messages.AddRange(pageInfo.Items);
}

// set messages state as read
foreach (var message in messages)
{
    client.SetRead(message.ItemId);
}