@Override
    public Socket accept() throws IOException {
      // It's expected that the GMSHealthMonitor will start shut down prior to calling this accept,
      // but to prevent hanging on the rare race where that doesn't happen, throw this exception.
      throw new IOException("Unable to handle accept call.");
    }
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