message: Document net_sync()
diff: @@ -171,6 +171,19 @@ fn net_sync_to<A: Api>(
  Ok(())
  }
  +/// Synchronize the local blockchain stored in `storage` with the
  +/// network `net`. That is, fetch all blocks between the most recent
  +/// block we received (as denoted by the `HEAD` tag) and the network's
  +/// current tip. Blocks will be packed into epochs on disk as soon
  +/// they're stable.
  +///
  +/// If `sync_once` is set to `true`, then this function will
  +/// synchronize once and then return. If it's set to `false`, then
  +/// this function will run forever, continuously synchronizing to the
  +/// network's latest tip. (In the case of the Hermes backend, it will
  +/// sleep for some time between polling for new tips; with the native
  +/// protocol backend, it will block waiting for the server to send us
  +/// new tip announcements.)
  pub fn net_sync<A: Api>(
  net: &mut A,
  net_cfg: &net::Config,
  