aio hang about jimtcl

[msteveb]

The socket is fully buffered so your puts typically won't be sent. Either make it line buffered or add '$f flush' after the last puts

[prpr19xx]

OK, it's an easy fix, but it breaks previously working code.
I note that the 0.82 release documentation didn't actually state what the default buffering mode was, nor does the current version say this has changed, but at least it now tells you what it is.

[msteveb]

The docs for aio buffering say:

Channels usually begin in full buffering mode, unless they identify
as a tty channel, in which case line buffering is used, and `stderr`
begins with no buffering.

And this is still true. With full buffering you can't rely on when the buffer is flushed without an explicit flush. If it worked before it was just "lucky" as a side effect of the implementation (probably that a switch from write to read caused a flush), but that is not part of the documented interface.