Test for backpressure when using Observable.interval

gistfile1.groovy

@Grab("io.reactivex:rxjava:1.0.8")
import rx.*
import static java.util.concurrent.TimeUnit.*
import static java.time.LocalTime.*

def sub = Observable.interval(1, SECONDS)
                    .doOnNext { tick-> 
                      println "tick $tick at ${now()}" 
                    }
                    .subscribe { tick ->
                      println "received tick $tick, sleeping..."
                      sleep 2_000
                      println "woke up after tick $tick"
                    }
sleep 60_000
sub.unsubscribe()