fileSystem.atomicMove(dirty, clean)
          val oldLength = entry.lengths[i]
          // TODO check null behaviour
          val newLength = fileSystem.metadata(clean).size ?: 0
          entry.lengths[i] = newLength
          size = size - oldLength + newLength
        }
      } else {
        fileSystem.deleteIfExists(dirty)
      }
    }

    entry.currentEditor = null
    if (entry.zombie) {

         * is at least expandedCapacity(n, n + 1) satisfies this property.
         */
        int newLength = ImmutableCollection.Builder.expandedCapacity(n, n + 1);
        if (newLength > elements.length) {
          elements = Arrays.copyOf(elements, newLength);
        }
      }
      elements[n++] = element;
      return this;
    }

    /**