[9fans] Detecting EOF vs. Interrupt across 9P

[Lyndon Nerenberg (VE6BBM/VE7TFX)]

Given a foofs which serves the writable file /mnt/foo, is there
any reliable way to distinguish between

        % cat > /mnt/foo
        type some
        text and quit
        ^D
        %

and

        % cat > /mnt/foo
        type some
        text, then change your mind and hit <DEL>
        %

at the server end?  I know I read something about this, somewhere, but
I can't find it now.  It could very well have been buried in some
source I was reading (about Tflush vs. 0 length Twrites or some
such?).

--lyndon