Improve ImmutableConciseSet.contains performance

[drcrallen]

#6 introduced ImmutableConciseSet.contains

Unfortunately, the method used is sub-optimal, as doing a ImmutableConciseSet.intersection is faster than the existing contains (see metamx/bytebuffer-collections#32 (comment) for related conversation)

This ask is to optimize ImmutableConciseSet.contains to match or exceed the performance of ImmutableConciseSet.intersection

[drcrallen]

Suggested benchmark in #9

[drcrallen]

ImmutableConciseSetBenchmark.timeContains: [measured 20 out of 30 rounds, threads: 1 (sequential)]
 round: 1.00 [+- 0.01], round.block: 0.00 [+- 0.00], round.gc: 0.00 [+- 0.00], GC.calls: 0, GC.time: 0.00, time.total: 30.04, time.warmup: 10.00, time.bench: 20.04
ImmutableConciseSetBenchmark.timeUnion: [measured 20 out of 30 rounds, threads: 1 (sequential)]
 round: 0.63 [+- 0.01], round.block: 0.00 [+- 0.00], round.gc: 0.00 [+- 0.00], GC.calls: 2, GC.time: 0.00, time.total: 19.19, time.warmup: 6.55, time.bench: 12.64

[msj100f]

Hello,I'm a chinese, thank you for reading this in the busy schedule. I have a question about ConciseSet class, but I can't find the way to contact you. can you help me?
My question:
I used ConciseSet in my project,It's no problem for most of the time, but somtimes it's a problem. Exception :
java.lang.ArrayIndexOutOfBoundsException
at it.uniroma3.mat.extendedset.rev157.intset.ConciseSet$WordIterator.flush(ConciseSet.java:1003)
at it.uniroma3.mat.extendedset.rev157.intset.ConciseSet$WordIterator.access$1000(ConciseSet.java:889)
at it.uniroma3.mat.extendedset.rev157.intset.ConciseSet.performOperation(ConciseSet.java:1102)
at it.uniroma3.mat.extendedset.rev157.intset.ConciseSet.add(ConciseSet.java:1974)

Can you help me? Thank you!

[msj100f]

I'm so sorry forget tell you my email(msj100f@163.com).