code: @Override
      public boolean retainAll(Collection<?> collection) {
          boolean didOmitAny = false;
          for (int offset = 0; offset < this.size; offset++) {
              if (!collection.contains(this.storage[offset])) {
                  System.arraycopy(this.storage, offset + 1, this.storage, offset, this.size - (offset + 1));
                  this.storage[--this.size] = null;
                  didOmitAny = true;
              }
          }
          return didOmitAny;
      }
docs: {@inheritDoc}