Seek to a position in the stream
@link http://www.php.net/manual/en/function.fseek.php
int $offset Stream offset:
int $whence Where the offset is applied:
bool Returns TRUE on success or FALSE on failure
Overrides StreamInterface::seek
public function seek($offset, $whence = SEEK_SET) {
return $this->cache[self::SEEKABLE] ? fseek($this->stream, $offset, $whence) === 0 : false;
}