using singleton list to save memory
using enummap instead enum
WELD-1793 Implement Event.fireAsync
WELD-1793 Testcase
WELD-1793 Make it possible to @Inject ExperimentalEvent
WELD-1793 Complex fireAsync testcase
WELD-1793 Implement EventMetadata.isAsync()
WELD-1793 Use Weld's ExecutorServices for dispatching async events
WELD-1807 Make it possible to use ForkJoinPool.commonPool() as Weld's ExecutorServices
WELD-1807 Use ForkJoinPool.commonPool() as the default executor in Weld SE
WELD-1793 Make it possible to specify an executor for asynchronous delivery of the given event