* In the Event the converter doesn't support the characters {&,#}[0-9],
* it will substitute the illegal sequence with the substitution characters.
* Note that codeUnit(32bit int eg: unit of a surrogate pair) is represented as
* &#144470; and Zero padding is ignored.</li>
* <li>UCNV_ESCAPE_XML_HEX:Substitues the ILLEGAL SEQUENCE with the decimal
* In the Event the converter doesn't support the characters {&,#}[0-9],
* it will substitute the illegal sequence with the substitution characters.
* Note that codeUnit(32bit int eg: unit of a surrogate pair) is represented as
* &#144470; and Zero padding is ignored.</li>
* <li>UCNV_ESCAPE_XML_HEX:Substitues the ILLEGAL SEQUENCE with the decimal