Expose ByteBufAllocator in ClientResources

[jwils]

To have more control over buffer allocation configuration, it would be
nice to include the option to choose what allocator to use.

[coveralls]

Coverage decreased (-0.2%) to 92.658% when pulling 59d7add on jwils:expose-allocator into c8c59ba on mp911de:master.

[coveralls]

Coverage decreased (-0.006%) to 92.844% when pulling acbfc81 on jwils:expose-allocator into c8c59ba on mp911de:master.

[mp911de]

Hi @jwils thanks for the PR. The code looks pretty decent. Could you help me understand your motivation for the change? Could this issue be solved by switching to ByteBufAllocator.DEFAULT?

[jwils]

If including netty from lettuce as a shaded jar it'll have to use a different PooledAllocator than other netty instance. The default allocator is configured to use up to 50% of memory so two or more instances can cause problem.

I can use the system properties to set each size if you want to minimize the parameters for ClientResources.

[mp911de]

Having a solution outside ClientResources would be my preferred solution. Using the shaded jar comes with several drawbacks and imposes constraints on applications. Reuse of netty resources (allocators, event loops) is no longer possible.

[mp911de]

Closing this PR for now.