private ByteString fetchTokenWithCurrentToken(final String appId) throws IOException, ServiceException {
    UserGroupInformation ugi = getUgiWithCurrentToken();
    return getTokenWithUgi(appId, ugi);
  }
Tries to fetch token by LlapManagementProtocolClientImpl from a daemon on the cluster.
Assumes that we already have a valid currentToken for communicating with the daemons.
llap-client/src/java/org/apache/hadoop/hive/llap/security/LlapTokenClient.java