Serializes element data directly to stream.
It is assumed that this method consumes the content (i.e. destroys the backing object) unless the data source also implements {@link OMDataSourceExt} and{@link OMDataSourceExt#isDestructiveWrite()} returns false
.
@param output destination stream for element XML text
@param format Output format information. The implementation must use this information to choose the correct character set encoding when writing to the output stream. This parameter must not be null.
@throws XMLStreamException