public void xml(String xml) {
    if (LogLevel.DEBUG < logConfiguration.logLevel) {
      return;
    }
    printlnInternal(LogLevel.DEBUG, logConfiguration.xmlFormatter.format(xml));
  }
Log a XML string, with level {@link LogLevel#DEBUG} by default.

@param xml the XML string to log
xlog/src/main/java/com/elvishew/xlog/Logger.java