message: Clone for StarlarkHasherBuilder
diff: @@ -19,6 +19,7 @@ use std::hash::BuildHasher;
  use std::hash::Hasher;
  use fnv::FnvHasher;
  +use gazebo::dupe::Dupe;
  use crate::hash_value::StarlarkHashValue;
  @@ -57,7 +58,7 @@ impl Hasher for StarlarkHasher {
  }
  }
  -#[derive(Default, Debug)]
  +#[derive(Default, Debug, Clone, Copy, Dupe)]
  pub struct StarlarkHasherBuilder;
  impl BuildHasher for StarlarkHasherBuilder {
  