Chore: refine

openraft/src/raft/mod.rs

@@ -400,10 +400,13 @@ where C: RaftTypeConfig
  self.inner.call_core(RaftMsg::InstallCompleteSnapshot { vote, snapshot, tx }, rx).await
  }
 
- /// Submit an InstallSnapshot RPC to this Raft node.
+ /// Receive an `InstallSnapshotRequest`.
  ///
  /// These RPCs are sent by the cluster leader in order to bring a new node or a slow node
- /// up-to-speed with the leader (§7).
+ /// up-to-speed with the leader.
+ ///
+ /// If receiving is finished `done == true`, it installs the snapshot to the state machine.
+ /// Nothing will be done if the input snapshot is older than the state machine.
  #[tracing::instrument(level = "debug", skip_all)]
  pub async fn install_snapshot(
  &self,