Defined in github.com/aws/aws-sdk-go/service/rds/api.go
A specific DB snapshot identifier to describe. This parameter cannot be used in conjunction with DBInstanceIdentifier. This value is stored as a lowercase string.
Must be 1 to 255 alphanumeric characters. First character must be a letter. Cannot end with a hyphen or contain two consecutive hyphens. If this identifier is for an automated snapshot, the SnapshotType parameter
must also be specified.