Method Gz._file()->seek()
- Method
seek
 intseek(intpos,void|inttype)- Description
 Seeks within the file.
- Parameter 
pos Position relative to the searchtype.
- Parameter 
type SEEK_SET = set current position in file to pos SEEK_CUR = new position is current+pos SEEK_END is not supported.
- Returns
 New position or negative number if seek failed.