Couchbase Threads are in BLOCKED state

Java SDK
1

We are doing the load testing of our application , which uses the Couchbase DB. We are taking the thread dumps at regular intervals. In all the thread dumps after making call to couchbase threads are in BLOCKED state. We are not understating this behaviour

Below is the configuration of couchbase environment

  DefaultCouchbaseEnvironment.builder().kvTimeout(5000).connectTimeout(7500)
                .viewTimeout(7500).queryTimeout(7500).disconnectTimeout(10000)
                .retryStrategy(BestEffortRetryStrategy.INSTANCE).build();

And we are doing simple CRUD operations like

                JsonDocument doc =
                        JsonDocument.create("1236",
                                JsonObject.create().put("name", "test"));
bucket.insert(doc);

Below is the stackstrace what we obtained from Jstack

Thread 4257: (state = BLOCKED)
 - sun.misc.Unsafe.park(boolean, long) @bci=0 (Compiled frame; information may be imprecise)
 - java.util.concurrent.locks.LockSupport.parkNanos(java.lang.Object, long) @bci=20, line=215 (Compiled frame)
 - java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireSharedNanos(int, long) @bci=139, line=1037 (Compiled frame)
 - java.util.concurrent.locks.AbstractQueuedSynchronizer.tryAcquireSharedNanos(int, long) @bci=25, line=1328 (Compiled frame)
 - java.util.concurrent.CountDownLatch.await(long, java.util.concurrent.TimeUnit) @bci=10, line=277 (Compiled frame)
 - com.couchbase.client.java.util.Blocking.blockForSingle(rx.Observable, long, java.util.concurrent.TimeUnit) @bci=32, line=72 (Compiled frame)
 - com.couchbase.client.java.CouchbaseBucket.get(java.lang.String, long, java.util.concurrent.TimeUnit) @bci=17, line=118 (Compiled frame)
 - com.couchbase.client.java.CouchbaseBucket.get(java.lang.String) @bci=9, line=113 (Compiled frame)

All our documents are in KBs. We have a cluster with 3 nodes. Java sdk version- 2.3.4

Please guide us in understanding the behaviour.

Thanks