exception
Global cache of compiled exception handler invokers, keyed by the reflective Method they were generated from.
As with eventInvokerCache, this avoids repeatedly invoking LambdaMetafactory for the same @ExceptionHandler method. Once an ExceptionInvoker has been created for a given Method, all subsequent subscriptions that discover an equal method will reuse the same invoker.
The cache is shared across all EventManager instances via the companion object. Entries are strongly referenced, which trades a small, bounded amount of memory for predictable, minimal overhead when wiring exception handlers.