public ApnsServerSocketBuilder asPool(ExecutorService executor) {
		this.executor = executor;
		return this;
	}
Constructs a pool of connections to the notification servers.

Apple servers recommend using a pooled connection up to 15 concurrent
persistent connections to the gateways.

Note: This option has no effect when using non-blocking connections.
src/test/java/com/notnoop/apns/ApnsServerSocketBuilder.java