code: public static <T, U> Consumer<Pair<T, U>> tupled(BiConsumer<T, U> consumer) {
          dbc.precondition(consumer != null, "cannot apply a pair to a null consumer");
          return pair -> consumer.accept(pair.first(), pair.second());
      }
docs: Adapts a binary consumer to an consumer accepting a pair.
  
  @param <T> the consumer first parameter type
  @param <U> the consumer second parameter type
  @param consumer the consumer to be adapted
  @return the adapted consumer