code: protected void writeNewLine(int indentation) throws XMLStreamException {
          final int newLineLength = getNewLine().length();
          final int prefixLength = newLineLength + (getIndent().length() * indentation);
          if (prefixLength > 0) {
              if (linePrefix == null) {
                  linePrefix = (getNewLine() + getIndent()).toCharArray();
              }
              while (prefixLength > linePrefix.length) {
                  // make linePrefix longer:
                  char[] newPrefix = new char[newLineLength
                          + ((linePrefix.length - newLineLength) * 2)];
                  System.arraycopy(linePrefix, 0, newPrefix, 0, linePrefix.length);
                  System.arraycopy(linePrefix, newLineLength, newPrefix, linePrefix.length,
                          linePrefix.length - newLineLength);
                  linePrefix = newPrefix;
              }
              out.writeCharacters(linePrefix, 0, prefixLength);
          }
      }
docs: Write a line separator followed by indentation.