fromListenableFuture
@Contract(value = "_ -> new")
@Contract(value = "_, _ -> new")
from
open fun <T> fromListenableFuture(listenableFuture: ListenableFuture<T>): ObservableFuture<T>
open fun <T> fromListenableFuture(listenableFuture: ListenableFuture<T>, executor: Executor): ObservableFuture<T>