Entry point for external libraries to add event types. Event types should be
<code>static</code> fields. EventType instances are compared by
reference.
<p>
Event types are best described by an <code>enum</code> that implements the
{@link EventType} interface, see {@link Event.Type}.
@return false if this particular EventType instance does not represent a
real event type but a guard value, example: extra enum value for
switch statements, see {@link Event.Type#NON_CORE_EVENT}
Entry point for external libraries to add event types. Event types should be <code>static</code> fields. EventType instances are compared by reference. <p> Event types are best described by an <code>enum</code> that implements the {@link EventType} interface, see {@link Event.Type}.