var activity int32
	rwm := NewLRWMutex()
	cdone := make(chan bool)
	go writer(rwm, numIterations, &activity, cdone)
	var i int
	for i = 0; i < numReaders/2; i++ {
		go reader(rwm, numIterations, &activity, cdone)
	}
	go writer(rwm, numIterations, &activity, cdone)
	for ; i < numReaders; i++ {
		go reader(rwm, numIterations, &activity, cdone)
	}
	// Wait for the 2 writers and all readers to finish.

		var activity int32
		cdone := make(chan bool)
		go writer(resource, numIterations, &activity, cdone)
		var i int
		for i = 0; i < numReaders/2; i++ {
			go reader(resource, numIterations, &activity, cdone)
		}
		go writer(resource, numIterations, &activity, cdone)
		for ; i < numReaders; i++ {
			go reader(resource, numIterations, &activity, cdone)
		}

		t.Fatal("Unlock timed out, which should not happen")
	case <-timer.C:
	}
}

// Borrowed from mutex_test.go
func HammerMutex(m *DRWMutex, loops int, cdone chan bool) {
	for range loops {
		m.Lock(id, source)
		m.Unlock(context.Background())
	}
	cdone <- true
}

// Borrowed from mutex_test.go
func TestMutex(t *testing.T) {
	loops := 200
	if testing.Short() {
		loops = 5
	}

      checkNotDone();
      digest.update(bytes);
    }

    private void checkNotDone() {
      checkState(!done, "Cannot re-use a Hasher after calling hash() on it");
    }

    @Override
    public HashCode hash() {
      checkNotDone();
      done = true;
      return (bytes == digest.getDigestLength())
          ? HashCode.fromBytesNoCopy(digest.digest())

      checkNotDone();
      checkNotNull(bytes);
      mac.update(bytes);
    }

    private void checkNotDone() {
      checkState(!done, "Cannot re-use a Hasher after calling hash() on it");
    }

    @Override
    public HashCode hash() {
      checkNotDone();
      done = true;
      return HashCode.fromBytesNoCopy(mac.doFinal());
    }
  }

      checkNotDone();
      digest.update(bytes);
    }

    private void checkNotDone() {
      checkState(!done, "Cannot re-use a Hasher after calling hash() on it");
    }

    @Override
    public HashCode hash() {
      checkNotDone();
      done = true;
      return (bytes == digest.getDigestLength())
          ? HashCode.fromBytesNoCopy(digest.digest())

		aws --endpoint-url http://localhost:"$start_port" s3api upload-part \
			--upload-id "$uploadId" --bucket bucket --key obj-1 \
			--part-number "$i" --body ./file-5mib
	done
	for i in {1..6}; do
		find ${WORK_DIR}/disk${i}/.minio.sys/multipart/ -type f -name "part.1" -delete
	done
	cat <<EOF >parts.json
{
    "Parts": [
        {
            "PartNumber": 1,
            "ETag": "5f363e0e58a95f06cbe9bbc662c5dfb6"
        },

		"${PWD}/mc" cp /etc/hosts minio/bucket/testobj

		sudo chown -R ${USER}. "${WORK_DIR}/disk${i}"
	done

	for vid in $("${PWD}/mc" ls --json --versions minio/bucket/testobj | jq -r .versionId); do
		"${PWD}/mc" cat --vid "${vid}" minio/bucket/testobj | md5sum
	done

	pkill minio
	sleep 3
}

function main() {
	start_port=$(shuf -i 10000-65000 -n 1)

	start_minio_4drive ${start_port}

	rv=$?

	pkill minio
	sleep 3

	if [ "$rv" -ne 0 ]; then
		for i in $(seq 0 1); do
			echo "server$i log:"
			cat "$WORK_DIR/pool-minio-900$i.log"
		done
	fi

	for i in $(seq 0 1); do
		rm -f "$WORK_DIR/pool-minio-900$i.log"
	done

	return "$rv"
}

function run_test_pool_erasure_sets_ipv6() {
	start_minio_pool_erasure_sets_ipv6

	export SERVER_ENDPOINT="[::1]:9000"

		t := time.NewTicker(updateTime)
		defer t.Stop()
		defer saverWg.Done()
		var lastSave time.Time

		for {
			select {
			case <-t.C:
				if cache.Info.LastUpdate.Equal(lastSave) {
					continue
				}
				scannerLogOnceIf(ctx, cache.save(ctx, er, dataUsageCacheName), "nsscanner-cache-update")
				updates <- cache.clone()

				lastSave = cache.Info.LastUpdate
			case v, ok := <-bucketResults: