Raynos/level-write-stream — pull request #1 by dominictarr (2014-08-25 16:32:28+00:00)
Title: a callback *must* be called exactly once.

this was calling each callback many times.
Each even registered another listener, and all the listeners where called every time a write finished.
That broke the counter in end-stream, meaning that a write stream never emitted the finish event.

need this patch for an upcoming pr to sublevel-migrate