Amazon web services Amazon Web服务-BegEncreateDbSnapshot

有人用过这个吗？我找不到任何代码示例

AmazonRDS rds = AWSClientFactory.CreateAmazonRDSClient(RegionEndpoint.USEast1);

CreateDBSnapshotRequest request = new CreateDBSnapshotRequest();
request.DBInstanceIdentifier = db;

object state = null;

rds.BeginCreateDBSnapshot(request, delegate(IAsyncResult ar) { }, state);

我想做的是创建备份，我已经可以这样做了，但我想在备份完成时得到通知，以便继续下一步