message: Payload recording methods of small network metrics need not take mutable `this` args
diff: @@ -420,7 +420,7 @@ impl Metrics {
  }
  /// Records an outgoing payload.
  - pub(crate) fn record_payload_out(this: &mut Weak<Self>, kind: MessageKind, size: u64) {
  + pub(crate) fn record_payload_out(this: &Weak<Self>, kind: MessageKind, size: u64) {
  if let Some(metrics) = this.upgrade() {
  match kind {
  MessageKind::Protocol => {
  @@ -466,7 +466,7 @@ impl Metrics {
  }
  /// Records an incoming payload.
  - pub(crate) fn record_payload_in(this: &mut Weak<Self>, kind: MessageKind, size: u64) {
  + pub(crate) fn record_payload_in(this: &Weak<Self>, kind: MessageKind, size: u64) {
  if let Some(metrics) = this.upgrade() {
  match kind {
  MessageKind::Protocol => {
  