docs: public CRDTTimestampedLong get(VectorClock observedTimestamps) {
          checkSessionConsistency(observedTimestamps);
          stateReadLock.lock();
          try {
              long value = 0;
              for (long[] pnValue : state.values()) {
                  value += pnValue[0];
                  value -= pnValue[1];
              }
              return new CRDTTimestampedLong(value, new VectorClock(stateVectorClock));
          } finally {
              stateReadLock.unlock();
          }
      }