code: public java.util.List<String> getReadReplicaDBClusterIdentifiers() {
          if (readReplicaDBClusterIdentifiers == null) {
              readReplicaDBClusterIdentifiers = new com.amazonaws.internal.SdkInternalList<String>();
          }
          return readReplicaDBClusterIdentifiers;
      }
docs: <p>
  Contains one or more identifiers of Aurora DB clusters to which the RDS DB instance is replicated as a Read
  Replica. For example, when you create an Aurora Read Replica of an RDS MySQL DB instance, the Aurora MySQL DB
  cluster for the Aurora Read Replica is shown. This output does not contain information about cross region Aurora
  Read Replicas.
  </p>
  <note>
  <p>
  Currently, each RDS DB instance can have only one Aurora Read Replica.
  </p>
  </note>
  
  @return Contains one or more identifiers of Aurora DB clusters to which the RDS DB instance is replicated as a
  Read Replica. For example, when you create an Aurora Read Replica of an RDS MySQL DB instance, the Aurora
  MySQL DB cluster for the Aurora Read Replica is shown. This output does not contain information about
  cross region Aurora Read Replicas.</p> <note>
  <p>
  Currently, each RDS DB instance can have only one Aurora Read Replica.
  </p>