The v2 of the java client leaks RxJava threads on shutdown

( Issue initially reported here : https://forums.couchbase.com/t/the-v2-of-the-java-client-leaks-rxjava-threads-on-shutdown/3890 )

We use the couchbase client v2.1.3 in a webapp application : in development we use hot redeployment and we got memory issues probably caused by the fact that RxJava Threads are not stopped when we close the couchbase client :
After few redeployments several duplicated RxJava Threads are present and a memory dump shows that they hold the old classloaders.

The issue is easy to reproduce in a simple main class :
Just create de couchbase client Cluster, connect to a Bucket and do a little query then stop the Cluster (Cluster.shutdown).
Then if you dump the threads and you see there are still some RxJava Threads :

In my case before Cluster shutdown, I have these threads :

• 13 : cb-io-1-4
• 25 : threadDeathWatcher-4-1
• 12 : cb-io-1-3
• 11 : cb-io-1-2
• 10 : cb-io-1-1
• 23 : cb-computations-4
• 22 : cb-computations-3
• 21 : cb-computations-2
• 20 : cb-computations-1
• 19 : cb-core-3-2
• 18 : cb-core-3-1
• 16 : RxComputationThreadPool-3
• 15 : RxComputationThreadPool-2
• 14 : RxComputationThreadPool-1
  (jvm threads ommitted)

And after the shutdown, there is still the following threads :

• 25 : threadDeathWatcher-4-1
• 23 : cb-computations-4
• 22 : cb-computations-3
• 21 : cb-computations-2
• 20 : cb-computations-1
• 16 : RxComputationThreadPool-3
• 15 : RxComputationThreadPool-2
• 14 : RxComputationThreadPool-1
  (jvm threads ommitted)

(dumping threads with :
ThreadInfo[] threadInfos = threadMXBean.getThreadInfo(threadMXBean.getAllThreadIds());
for(ThreadInfo ti : threadInfos)

{ System.out.printf(" - %s : %s%n",ti.getThreadId(), ti.getThreadName()); }

)