@Deprecated
  public static AuthenticationProtos.Token toToken(Token<AuthenticationTokenIdentifier> token) {
    return ClientTokenUtil.toToken(token);
  }
See {@link ClientTokenUtil#toToken(Token)}.
@deprecated External users should not use this method, will be removed in 4.0.0. Please post on
            the HBase dev mailing list if you need this method. Internal HBase code should use
            {@link ClientTokenUtil} instead.
hbase-server/src/main/java/org/apache/hadoop/hbase/security/token/TokenUtil.java