code: public static void onLastOperator(Function<? super Publisher<Object>, ? extends Publisher<Object>> onLastOperator) {
  		onLastOperator(onLastOperator.toString(), onLastOperator);
  	}
docs: Add a {@link Publisher} operator interceptor for the last operator created
  in every flow ({@link Flux} or {@link Mono}). The passed function is applied
  to the original operator {@link Publisher} and can return a different {@link Publisher},
  on the condition that it generically maintains the same data type as the original.
  <p>
  Note that sub-hooks are cumulative, but invoking this method twice with the same
  instance (or any instance that has the same `toString`) will result in only a single
  instance being applied. See {@link #onLastOperator(String, Function)} for a variant
  that allows you to name the sub-hooks (and thus replace them or remove them individually
  later on). Can be fully reset via {@link #resetOnLastOperator()}.
  <p>
  This pointcut function cannot make use of {@link Flux}, {@link Mono} or
  {@link ParallelFlux} APIs as it would lead to a recursive call to the hook: the
  operator calls would effectively invoke onEachOperator from onEachOperator.
  
  @param onLastOperator the sub-hook: a function to intercept last operation call
  (e.g. {@code map(fn2)} in {@code flux.map(fn).map(fn2).subscribe()})
  
  @see #onLastOperator(String, Function)
  @see #resetOnLastOperator(String)
  @see #resetOnLastOperator()
  @see #onEachOperator(Function)