stream: pipeline callback fix

Potential fix for #40279

I wrote a test similar to the code sample in the issue. With some debugging, I noticed that the eos callback wasn't being called for the middle PassThrough stream. Neither onend nor onclose were called, but onfinish was. I followed the code path and added a read(0) in hopes of triggering the end of the readable, which would call the callback. This worked for the test case I wrote (I haven't gotten it to work with a more generic test case though). If you comment out the if-clause I added, the pipeline should time out.