@Override
    public boolean isClosed() {
      final boolean closed = wrappedSocket.isClosed();
      lock.lock();
      if (firstWait) {
        firstWait = false;
        try {
          block.await();
        } catch (InterruptedException e) {
          e.printStackTrace();
        }
      }
      lock.unlock();
      return closed;
    }
Establish the currentTimeStamp for the health monitor. This is the timestamp
used in contactedBy() updates and is usually established by the Monitor thread
in GMSHealthMonitor but is initially zero.

@return the timestamp
geode-membership/src/integrationTest/java/org/apache/geode/distributed/internal/membership/gms/fd/GMSHealthMonitorJUnitTest.java