I think we have fixed this bug in other pull-streams,
for example
https://github.com/pull-stream/stream-to-pull-stream/commit/5b3ebd83cc540d163c232c02d56bb20593f3db35

since pull-buffer reads in a loop, if it happens to be sync (if a big queue has built up) then it can blow the stack. The simplest way to fix is to use nextTick, but the best way is to detect if it's sync and use iteration.

I made https://www.npmjs.com/package/looper to solve that problem.