The type of source that will be generating the events. For example, if you want to be notified of events generated by a DB instance, you
            would set this parameter to db-instance. if this value is not specified, all events are returned. Valid values: db-instance |
            db-parameter-group | db-security-group | db-snapshot
             
            
 Declaration Syntax
 Declaration Syntax| C# | 
public string SourceType { get; set; }