def to_json
      JSON.pretty_generate({
        rds_instance:   rds_id,
        account_name:   account_name,
        backup_status:  status,
        status_message: message,
        status_url:     status_url,
        files:          files,
      })
    end
def to_json
      JSON.pretty_generate({
        rds_instance:   rds_id,
        account_name:   account_name,
        backup_status:  status,
        status_message: message,
        status_url:     status_url,
        files:          files,
      })
    end
Constructor.
 @param [String] rds_instance_id the ID of the RDS instance to backup
 @param [Hash] optional_params optional additional parameters:
  - :email - an email address to be notified on completion
  - :backup_id - a unique ID for this job, if necessary
  - :requested - a Time when this job was requested
  - :logger - a Logger object, for printing this job's ongoing status
 returns a JSON-format String representation of this backup job