@Override
    public DBCluster failoverDBCluster(FailoverDBClusterRequest request) {
        request = beforeClientExecution(request);
        return executeFailoverDBCluster(request);
    }
<p>
Forces a failover for a DB cluster.
</p>
<p>
For an Aurora DB cluster, failover for a DB cluster promotes one of the Aurora Replicas (read-only instances) in
the DB cluster to be the primary DB instance (the cluster writer).
</p>
<p>
For a Multi-AZ DB cluster, after RDS terminates the primary DB instance, the internal monitoring system detects
that the primary DB instance is unhealthy and promotes a readable standby (read-only instances) in the DB cluster
to be the primary DB instance (the cluster writer). Failover times are typically less than 35 seconds.
</p>
<p>
An Amazon Aurora DB cluster automatically fails over to an Aurora Replica, if one exists, when the primary DB
instance fails. A Multi-AZ DB cluster automatically fails over to a readable standby DB instance when the primary
DB instance fails.
</p>
<p>
To simulate a failure of a primary instance for testing, you can force a failover. Because each instance in a DB
cluster has its own endpoint address, make sure to clean up and re-establish any existing connections that use
those endpoint addresses when the failover is complete.
</p>
<p>
For more information on Amazon Aurora DB clusters, see <a
href="https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/CHAP_AuroraOverview.html"> What is Amazon
Aurora?</a> in the <i>Amazon Aurora User Guide</i>.
</p>
<p>
For more information on Multi-AZ DB clusters, see <a
href="https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/multi-az-db-clusters-concepts.html"> Multi-AZ DB
cluster deployments</a> in the <i>Amazon RDS User Guide</i>.
</p>

@param failoverDBClusterRequest
@return Result of the FailoverDBCluster operation returned by the service.
@throws DBClusterNotFoundException
        <code>DBClusterIdentifier</code> doesn't refer to an existing DB cluster.
@throws InvalidDBClusterStateException
        The requested operation can't be performed while the cluster is in this state.
@throws InvalidDBInstanceStateException
        The DB instance isn't in a valid state.
@sample AmazonRDS.FailoverDBCluster
@see <a href="http://docs.aws.amazon.com/goto/WebAPI/rds-2014-10-31/FailoverDBCluster" target="_top">AWS API
     Documentation</a>
aws-java-sdk-rds/src/main/java/com/amazonaws/services/rds/AmazonRDSClient.java