If a stream was marked as using delimeters (and pipes
always
were), a delimeter was inserted after every write(2). So
write(2) generated an empty message, and read(2) returned it.
And this lived on in the IL network protocol. I've always thought that was
one of the more elegant aspects of IL, but of course it didn't have a hope
in hell of surviving outside the Plan 9 ecosystem.
--lyndon