Re-evaluate the usefulness of `Pulse.take` and `Pulse.takeWhile`

[kevincianfarini]

If they're not actually useful, then make Pulse.beat return Nothing.

[kevincianfarini]

Rather than forcing every Pulse to be infinite, these functions could be removed and a beatWhile function could be added. Then the API becomes:

class Pulse {
  suspend fun beat(strategy: PulseBackpressureStrategy, action: suspend (Instant) -> Unit): Nothing
  suspend fun beatWhile(strategy: PulseBackpressureStrategy, action: suspend (Instant) -> Boolean): Unit
}