-pool.emitter.on(PoolEvents.full, () => console.info('Pool is full'))
-pool.emitter.on(PoolEvents.ready, () => console.info('Pool is ready'))
-pool.emitter.on(PoolEvents.busy, () => console.info('Pool is busy'))
+pool.emitter?.on(PoolEvents.full, () => console.info('Pool is full'))
+pool.emitter?.on(PoolEvents.ready, () => console.info('Pool is ready'))
+pool.emitter?.on(PoolEvents.busy, () => console.info('Pool is busy'))