Reduce memory footprint of Recyclers

[franz1981]

Currently Recycler(s) uses mpsc queues from JCTools, which:

• could not be used at all and just relies on the local array queue (it is what happen if the chunk size capacity is good enough - which is 32 by default (see

  netty/common/src/main/java/io/netty/util/Recycler.java

  Line 315 in fee3c39

  pooledHandles = (MessagePassingQueue<DefaultHandle<T>>) newMpscQueue(chunkSize, maxCapacity);

  )
• being allocated using padded variant of JCTools

I believe things could be improved by both making the allocations of such queues lazy AND using atomic unpadded or unpadded unsafe variant, while allocated.

We just need a new release of JCTools (from the dear @nitsanw) in order to have both the unpadded flavours in (if unsafe isn't present).

[nitsanw]

Will get to it next week

[franz1981]

If I can help and learn how to roll the release I will, Nitsan, just ping me on Gmail/github