Implementation for resolving event name to event type.
The implementation assigned a unique identifier to each event type. For Class-based event types, only one EventType instance and one event type id exists for the same class.
Event type names must be unique, that is an name must resolve to a single event type.
Each event type can have multiple names defined for it. For example, expressions such as "select * from A" and "select * from B" in which A and B are names for the same class X the select clauses each fireStatementStopped for events of type X. In summary, names A and B point to the same underlying event type and therefore event type id.