message: Exposing min/max value interface on MultiValuedFastField Reader
  Exposing min/max value interface on MultiValuedFastField Reader
diff: @@ -46,6 +46,24 @@ impl<Item: FastValue> MultiValuedFastFieldReader<Item> {
  self.vals_reader.get_range_u64(range.start, &mut vals[..]);
  }
  + /// Returns the minimum value for this fast field.
  + ///
  + /// The max value does not take in account of possible
  + /// deleted document, and should be considered as an upper bound
  + /// of the actual maximum value.
  + pub fn min_value(&self) -> Item {
  + self.vals_reader.max_value()
  + }
  +
  + /// Returns the maximum value for this fast field.
  + ///
  + /// The max value does not take in account of possible
  + /// deleted document, and should be considered as an upper bound
  + /// of the actual maximum value.
  + pub fn max_value(&self) -> Item {
  + self.vals_reader.min_value()
  + }
  +
  /// Returns the number of values associated with the document `DocId`.
  pub fn num_vals(&self, doc: DocId) -> usize {
  let range = self.range(doc);
  