From time to time i see ppl using data instead of body which is wrong.
happened just recently in node-fetch/node-fetch#481 (comment)

how do you feel about adding a little warning message that can only appear once. (kinda like node reports that you are using experimental apis)

if ('data' in bodyInit && notWarned) {
  console.warn('use body i

Just what the title says ... I logged in to last.fm with no apparent issues. Nuclear appears to be scrobbling correctly.

Clicking the Import button for Last.fm Favorites gives: "Error: Invalid number of favorites [2664]"

apply and of require both F[_] and A parameters, which often has inference issues requiring the user to annotate. Instead these methods could use the partial apply "trick" to infer at least the A type.

def apply[F[_], A](initial: A)(implicit arg0: Concurrent[F]): F[SignallingRef[F, A]]

Other data types might have similar issues, but this is the one I've noticed so fa