refactor flatMap_
Add flatMapWithConcurrencyLimit
build js
add rateLimit, flatMapConcat
build js
spec for flatMapConcat
buffer events, not spawned streams
toString implementations for new methods
build js
add holdWhen
add toString
improve naming
build js
add failing test
fix holdWhen
support truthy start value holdWhen
build js
add failing test for holdWhen flushing huge buffers
a bit more performant holdWhen impl
add test for maximum fold length. Currently 5000 passes on node