The LogFile property is used to specify the name of a file 
          that will contain a log of all client activity. The LogFormat 
          and LogLevel properties affect the specific format for the file 
          and the level of detail included in the log. It is recommended that 
          you specify an absolute path to the log file, otherwise the path will 
          be relative to the current working directory. You may include 
          environment variables in the path surrounded by percent (%) symbols 
          and they will be expanded.
          If the log file does not exist it will be created when the server 
          is started. If file already exists, the server will append the new 
          logging data to the file. The server must have permission to create 
          and/or modify the specified file.
          Setting this property to an empty string after the server has been 
          started will have the effect of disabling logging, setting the logging 
          level to 0 and the logging format to httpLogNone.