@Override
      Entry<E> result(int entryIndex) {
        return backingMap.getEntry(entryIndex);
      }
    };
  }

  /** Allocation-free implementation of {@code target.addAll(this)}. */
  void addTo(Multiset<? super E> target) {
    checkNotNull(target);
    for (int i = backingMap.firstIndex(); i >= 0; i = backingMap.nextIndex(i)) {
      target.add(backingMap.getKey(i), backingMap.getValue(i));
    }
  }

                        stream(toAddresses).of(stream -> stream.map(String::trim).forEach(address -> {
                            postcard.addTo(address);
                        }));
                    } else {
                        postcard.addTo(fessConfig.getMailFromAddress());
                        postcard.dryrun();
                    }

                postcard.addReplyTo(fessConfig.getMailReturnPath());
                stream(toAddresses).of(stream -> stream.forEach(address -> {
                    postcard.addTo(address);
                }));
                BeanUtil.copyMapToBean(dataMap, postcard);
            });
            saveInfo(messages -> messages.addSuccessSendTestmail(GLOBAL));

  @CanIgnoreReturnValue
  public static <T extends @Nullable Object> boolean addAll(
      Collection<T> addTo, Iterable<? extends T> elementsToAdd) {
    if (elementsToAdd instanceof Collection) {
      Collection<? extends T> c = (Collection<? extends T>) elementsToAdd;
      return addTo.addAll(c);
    }
    return Iterators.addAll(addTo, checkNotNull(elementsToAdd).iterator());
  }

  /**