sourceIdentifier
The identifier of the event source for which events will be returned. If this parameter is not specified, then all sources are included in the response.
Constraints:
If SourceIdentifier is supplied, SourceType must also be provided.
Specify a cluster identifier when SourceType is
cluster.Specify a cluster security group name when SourceType is
cluster-security-group.Specify a cluster parameter group name when SourceType is
cluster-parameter-group.Specify a cluster snapshot identifier when SourceType is
cluster-snapshot.