The number of days to retain automated backups. Setting this parameter to a positive number enables backups. Setting this parameter to 0
            disables automated backups. Changing this parameter can result in an outage if you change from 0 to a non-zero value or from a non-zero
            value to 0. These changes are applied during the next maintenance window unless the ApplyImmediately parameter is set to true
            for this request. If you change the parameter from one non-zero value to another non-zero value, the change is asynchronously applied as
            soon as possible. Default: Uses existing setting Constraints: 
- Must be a value from 0 to 35
- Can be specified for a read replica only if the source is running MySQL 5.6
- Cannot be set to 0 if the DB instance is a source to read replicas
 Declaration Syntax
 Declaration Syntax| C# | 
public int BackupRetentionPeriod { get; set; }