The identifier of the event source for which events will be returned. If not specified, then all sources are included in the response. Constraints:

• If SourceIdentifier is supplied, SourceType must also be provided.
• If the source type is DBInstance, then a DBInstanceIdentifier must be supplied.
• If the source type is DBSecurityGroup, a DBSecurityGroupName must be supplied.
• If the source type is DBParameterGroup, a DBParameterGroupName must be supplied.
• If the source type is DBSnapshot, a DBSnapshotIdentifier must be supplied.
• Cannot end with a hyphen or contain two consecutive hyphens.

public string SourceIdentifier { get; set; }