If you add a listener for 'data', or call stream.resume() then it'll start flowing data as it receives it, just like v0.8 and before. The only caveat is that listening for 'end' will not automatically start the flow of data, so you do sometimes have to either call resume() or add a data listener.

In practice, it's rare that you care about the end of the stream, but not about the data coming through it, except in tests.

tl;dr Your existing programs will almost certainly Just Work.