Fix to support .push() in .transform().
fix to compatible with new Stream2 with .push in ._transform()
hmm. Seems like a failure in v0.9.12.
Let me see how this works in 0.10.x
Tests passed in 0.8.x and 0.10.x
This PR is outdated but the fix it outlines still works. If I fix it up will you merge @TooTallNate ?