protected void indent() throws IOException {
        String indent = format.getIndent();
        if ( indent != null && !indent.isEmpty()) {
            for ( int i = 0; i < indentLevel; i++ ) {
                writer.write(indent);
            }
        }
    }
Writes the attributes of the given element
@param element the element whose attributes should be written
@throws IOException if the element could not be written
xmppserver/src/main/java/org/jivesoftware/util/XMLWriter.java