Hi guys, I still keep on my eyes on Radix project!

This issue came from the first time that I applied Radix in our production product. We noticed that our latency was slightly slower by 1~2 ms and we've got the hint from the pprof. We saw some of pipelining relative codes are showed up in profiling image.

I've tried a simple test with the latest commit and this is the result.

• Common Option
  • Benchmark Machine CPU: 20 CPU
  • Redis version: 4.0.10 (3 shards * 2 nodes)
  • Pool Size: 20

Option 1) With implicit pipelining (no other options)

Benchmark/hkeys-40                 5000000             10041 ns/op             282 B/op          7 allocs/op

Option 2) Without implicit pipelining and add options

• radix.PoolPipelineWindow(0, 0)
• radix.PoolOnEmptyCreateAfter(0)

Benchmark/hkeys-40                 5000000              9079 ns/op             307 B/op          7 allocs/op

We're handling 25,000+ req/s in our production service, and I think 1000 ns difference can be affected our latency. Any ideas on this?