message: Remove unneeded BTreeMap from ArchivableIndexMap
diff: @@ -3,12 +3,11 @@ use core::hash::Hash;
  use indexmap::IndexMap;
  use rkyv::{Archive, Deserialize, Serialize};
  #[cfg(feature = "std")]
  -use std::{collections::BTreeMap, hash::Hash};
  +use std::hash::Hash;
  #[derive(Serialize, Deserialize, Archive)]
  /// Rkyv Archivable IndexMap
  pub struct ArchivableIndexMap<K: Hash + Ord + Archive, V: Archive> {
  - indices: BTreeMap<K, u64>,
  entries: Vec<(K, V)>,
  }
  @@ -17,12 +16,10 @@ impl<K: Hash + Ord + Archive + Clone, V: Archive> From<IndexMap<K, V>>
  {
  fn from(it: IndexMap<K, V>) -> ArchivableIndexMap<K, V> {
  let mut r = ArchivableIndexMap {
  - indices: BTreeMap::new(),
  entries: Vec::new(),
  };
  let mut i: u64 = 0;
  for (k, v) in it.into_iter() {
  - r.indices.insert(k.clone(), i);
  r.entries.push((k, v));
  i += 1;
  }
  