MS Graphでメール送信

// MS Graph Clientインスタンスの作成
var cli = new GraphServiceClient(cred);
// メッセージの作成
var mesg = new Microsoft.Graph.Me.SendMail.SendMailPostRequestBody() {
    Message = new Message() {
        Subject = "メール送信テスト",
        Body = new ItemBody() {
            ContentType = BodyType.Text,
            Content = "メール送信てすとだよぅ"
        },
		// To
        ToRecipients = new List<Recipient>() {
            new Recipient() {
                EmailAddress = new EmailAddress() {
                    Address = "boo@foo.com"
                }
            }
        },
		// Cc
        CcRecipients = new List<Recipient>() {
            new Recipient() {
                EmailAddress = new EmailAddress() {
                    Address = "foo@woo.com"
                }
            }
        },
		// 添付
        Attachments = new List<Attachment>() {
            new FileAttachment() {
                Name = "hoge.png",
                ContentType = "image/png",
                ContentBytes = buff
            }
        }
    },
    SaveToSentItems = true
};
// メール送信
await cli.Me.SendMail.PostAsync(mesg);