quartzjer/node-http-proxy — comment on commit 1b077d23d74261304151455499e0b2ee2b3eae7d
File:  line 0
By quartzjer:

without this it oversubscribes the drain function, I don't know for sure if there's any functional difference in the block and tackling, but it definitely is friendlier to event emitter when there's lots of data writes happening :)