docs: protected String getHostHeader() {
          if (m_hostHeader != null) {
              return m_hostHeader;
          }
  
          if (!httpAdminListener.m_publicIntf.isEmpty()) {
              m_hostHeader = httpAdminListener.m_publicIntf;
              return m_hostHeader;
          }
  
          InetAddress addr = null;
          int httpPort = VoltDB.DEFAULT_HTTP_PORT;
          try {
              String localMetadata = VoltDB.instance().getLocalMetadata();
              JSONObject jsObj = new JSONObject(localMetadata);
              JSONArray interfaces = jsObj.getJSONArray("interfaces");
              //The first interface is external interface if specified.
              String iface = interfaces.getString(0);
              addr = InetAddress.getByName(iface);
              httpPort = jsObj.getInt("httpPort");
          } catch (Exception e) {
              m_log.warn("Failed to get HTTP interface information.", e);
          }
          if (addr == null) {
              addr = org.voltcore.utils.CoreUtils.getLocalAddress();
          }
          //Make the header string.
          m_hostHeader = addr.getHostAddress() + ":" + httpPort;
          return m_hostHeader;
      }