message: Use `u64` for nanosecond timestamps, as 200 years are plenty of time
diff: @@ -72,7 +72,9 @@ pub enum Message<P> {
  #[derive(Clone, Debug, Deserialize, Eq, Hash, PartialEq, Serialize)]
  pub struct Endpoint {
  /// UNIX timestamp in nanoseconds resolution.
  - timestamp_ns: u128,
  + ///
  + /// Will overflow earliest November 2262.
  + timestamp_ns: u64,
  /// Socket address the node is listening on.
  addr: net::SocketAddr,
  /// Certificate.
  @@ -169,7 +171,7 @@ where
  let our_endpoint = Endpoint {
  timestamp_ns: time::SystemTime::now()
  .duration_since(time::UNIX_EPOCH)?
  - .as_nanos(),
  + .as_nanos() as u64,
  addr,
  cert: tls::validate_cert(cert.clone())?,
  };
  