code: public static void onErrorDropped(Throwable e, Context context) {
  		Consumer<? super Throwable> hook = context.getOrDefault(Hooks.KEY_ON_ERROR_DROPPED,null);
  		if (hook == null) {
  			hook = Hooks.onErrorDroppedHook;
  		}
  		if (hook == null) {
  			log.error("Operator called default onErrorDropped", e);
  			throw Exceptions.bubble(e);
  		}
  		hook.accept(e);
  	}
docs: An unexpected exception is about to be dropped.
  <p>
  If no hook is registered for {@link Hooks#onErrorDropped(Consumer)}, the dropped
  error is logged at ERROR level and thrown (via {@link Exceptions#bubble(Throwable)}.
  
  @param e the dropped exception
  @param context a context that might hold a local error consumer