Currently, channel.seek is used to change the offset at which the next I/O on the channel will occur. Implicitly this changes the start of the file region that the channel can access. Optionally, an end parameter can be used to also change the end of the file region.
Issues:
Should setting the file region be done via a separate method?
Should it be possible to query the region associated with a channel?
seek throws if the channel is not seekable. Is this desirable?