message: Added Send and Sync to the Query trait.
diff: @@ -40,7 +40,7 @@ use std::fmt;
  ///
  /// When implementing a new type of `Query`, it is normal to implement a
  /// dedicated `Query`, `Weight` and `Scorer`.
  -pub trait Query: QueryClone + downcast_rs::Downcast + fmt::Debug {
  +pub trait Query: QueryClone + Send + Sync + downcast_rs::Downcast + fmt::Debug {
  /// Create the weight associated to a query.
  ///
  /// If scoring is not required, setting `scoring_enabled` to `false`
  