seek64
seek64(offset: Integer64);
The seek64 method of the File class sets the file pointer to the position (in file units from the beginning of the file) specified in the offset parameter. The seek64 method automatically opens the file if it is not already open.
For Unicode text, the file unit is character (not byte). For Unicode text files that contain a Unicode File Marker, the file marker specified in the unicodeBOM property is ignored. The next read or write operation occurs from the specified position.