code: public final HttpClient doOnRequest(BiConsumer<? super HttpClientRequest, ? super Connection> doOnRequest) {
  		Objects.requireNonNull(doOnRequest, "doOnRequest");
  		return new HttpClientDoOn(this, doOnRequest, null, null, null);
  	}
docs: Setup a callback called when {@link HttpClientRequest} is about to be sent.
  
  @param doOnRequest a consumer observing connected events
  
  @return a new {@link HttpClient}