refactor(iroh, iroh-relay)!: Do reconnection in ActiveRelayActor (#3058)

## Description

This moves the reconnection logic ingo ActiveRelayActor instead of
doing this in the RelayActor.  The logic itself is not really changed.
This does simplify things a fair bit though, it is a lot easier to do
this in one place where all the state needs to be.

In the grand scheme of things this moves "logical" control over the
relay Client entirely into the ActiveRelayActor.

Some small side effects:

- The ActiveRelayMessage::Ping and ActiveRelayMessage::GetLocalAddr
  messages are no longer needed.  Though I decided to keep the latter
  for testing purposes.

- ActiveRelayMessage::NotePreferred has been rename to SetHomeRelay.
  Since the ActiveRelayActor now reconnects to relays on its own it
  needs to keep track of whether it is the home relay itself as well.

- The duplicate ping task tracking in the RelayActor is removed.  This
  is still not ideal in the ActiveRelayActor because it still blocks
  this actor.  But that's no regression and to be addressed when the
  relay Client is no longer an actor.

- RelayActor::close_and_reconnect_relay and
  RelayActor::send_to_active_relay are no longer needed.  Because we
  await all the ActiveRelayActor tasks already we do not need to
  manually track them in case they need to be closed.

- The ClientBuilder was no longer using is_preferred, so remove this.

## Breaking Changes

### iroh-relay

- `ClientBuilder::is_preferred` no longer exists. Set the preference
once the client exists instead.

## Notes & open questions

<!-- Any notes, remarks or open questions you have to make about the PR.
-->

## Change checklist

- [x] Self-review.
- [x] Documentation updates following the [style
guide](https://rust-lang.github.io/rfcs/1574-more-api-documentation-conventions.html#appendix-a-full-conventions-text),
if relevant.
- [x] Tests if relevant.
- [x] All breaking changes documented.

Author: flub

iroh-relay/src/client.rs

@@ -192,8 +192,6 @@ impl PingTracker {
 /// Build a Client.
 #[derive(derive_more::Debug)]
 pub struct ClientBuilder {
-    /// Default is false
-    is_preferred: bool,
     /// Default is None
     #[debug("address family selector callback")]
     address_family_selector: Option<Box<dyn Fn() -> bool + Send + Sync>>,
@@ -218,7 +216,6 @@ impl ClientBuilder {
     /// Create a new [`ClientBuilder`]
     pub fn new(url: impl Into<RelayUrl>) -> Self {
         ClientBuilder {
-            is_preferred: false,
             address_family_selector: None,
             is_prober: false,
             server_public_key: None,
@@ -258,13 +255,6 @@ impl ClientBuilder {
         self
     }
 
-    /// Indicate this client is the preferred way to communicate
-    /// to the peer with this client's [`PublicKey`]
-    pub fn is_preferred(mut self, is: bool) -> Self {
-        self.is_preferred = is;
-        self
-    }
-
     /// Indicates this client is a prober
     pub fn is_prober(mut self, is: bool) -> Self {
         self.is_prober = is;
@@ -320,7 +310,7 @@ impl ClientBuilder {
 
         let inner = Actor {
             secret_key: key,
-            is_preferred: self.is_preferred,
+            is_preferred: false,
             relay_conn: None,
             is_closed: false,
             address_family_selector: self.address_family_selector,
@@ -432,6 +422,8 @@ impl Client {
 
     /// Send a ping to the server. Return once we get an expected pong.
     ///
+    /// This has a built-in timeout `crate::defaults::timeouts::PING_TIMEOUT`.
+    ///
     /// There must be a task polling `recv_detail` to process the `pong` response.
     pub async fn ping(&self) -> Result<Duration, ClientError> {
         self.send_actor(ActorMessage::Ping).await

iroh-relay/src/client/conn.rs

@@ -98,7 +98,7 @@ impl Conn {
     ///
     /// Errors if the packet is larger than [`MAX_PACKET_SIZE`]
     pub async fn send(&self, dst: NodeId, packet: Bytes) -> Result<()> {
-        trace!(%dst, len = packet.len(), "[RELAY] send");
+        trace!(dst = dst.fmt_short(), len = packet.len(), "[RELAY] send");
 
         self.inner
             .writer_channel

iroh-relay/src/server/actor.rs

@@ -142,7 +142,12 @@ impl Actor {
     async fn handle_message(&mut self, msg: Message) {
         match msg {
             Message::SendPacket { dst, data, src } => {
-                trace!(?src, ?dst, len = data.len(), "send packet");
+                trace!(
+                    src = src.fmt_short(),
+                    dst = dst.fmt_short(),
+                    len = data.len(),
+                    "send packet"
+                );
                 if self.clients.contains_key(&dst) {
                     match self.clients.send_packet(&dst, Packet { data, src }).await {
                         Ok(()) => {