TextIO.closeOut failure

[Stephen Weeks]

What is the correct thing to do when TextIO.closeOut is called on an outstream
whose buffer needs to be flushed, but the underlying write fails?  I'm pretty
sure I should raise an exception (which is currently being done), but I'm not
quite sure what to do with the state of the outstream.  Should I call close on
the underlying file descriptor?  Should I mark the outstream as closed
(preventing subsequent calls to closeOut from flushing the buffer)?