max_file_size()
|  Realscanner to test email's size.
|  
|  Usage: max_file_size(size,name='FileSizeOverrun')
|  
|  Where: size is a number of bytes, which if exceeded, virus is returned
|         name is a string, which identifies the virus name.
|            If this parameter is not present, 'FileSizeOverrun' is returned.
|  
|  Example: max_file_size(1024*1024*10)
|           # all files at least 10MB will be reported as virus