cacheSize=-1 option for toD endpoint does not completely disabling it

Even "cacheSize=1" is set to disable caching, still Endpoint object is cached.
Actually, by using org.apache.camel.impl.ProducerCache.pool member variable, Endpoint object will be cached into org.apache.camel.spi.ServicePool.

This is the stacktrace when Endpoint object is cached.

EmptyProducerCache(ProducerCache).doGetProducer(Endpoint, boolean) line: 450	
EmptyProducerCache(ProducerCache).doInAsyncProducer(Endpoint, Exchange, ExchangePattern, AsyncCallback, AsyncProducerCallback) line: 311	
SendDynamicProcessor.process(Exchange, AsyncCallback) line: 119

EmptyProducerCache class does not override ProducerCache.doInAsyncProducer() method, so doGetProducer(endpoint, true) is invoked. "true" leads to enable the cache option.

Please consider to override ProducerCache.doInAsyncProducer() method, and invode doGetProdcuer() method with (endpoint, false).