code: public void addToBlacklist(HostAddress hostAddress) {
      if (hostAddress != null && !isExplicitClosed()) {
        blacklist.putIfAbsent(hostAddress, System.nanoTime());
      }
    }
docs: After a failover, put the hostAddress in a static list so the other connection will not take
  this host in account for a time.
  
  @param hostAddress the HostAddress to add to blacklist