code: void insertValueAtPosition(final T value, final int pos) {
      if ((pos < 0) || (pos >= getNumSamples())) {
        throw new SketchesArgumentException("Insert position must be between 0 and "
                + getNumSamples() + ", " + "inclusive. Received: " + pos);
      }
  
      data_.set(pos, value);
    }
docs: Useful during union operation to force-insert a value into the union gadget. Does
  <em>NOT</em> increment count of items seen.
  
  @param value The entry to store in the reservoir
  @param pos   The position at which to store the entry