@Override
      public Token<AuthenticationTokenIdentifier> run() throws Exception {
        return obtainToken(conn);
      }
Obtain and return an authentication token for the given user.
@param conn The HBase cluster connection
@param user The user to obtain a token for
@return the authentication token instance
hbase-client/src/main/java/org/apache/hadoop/hbase/security/token/ClientTokenUtil.java