feat(API): Use mio::Token based polling

Avoid polling every single IO source to collect events,
poll those specific IO sources mio tells us about.

wireguard-broker/src/brokers/mio_client.rs

@@ -16,6 +16,7 @@ use crate::{SerializedBrokerConfig, WireGuardBroker, WireguardBrokerMio};
 #[derive(Debug)]
 pub struct MioBrokerClient {
     inner: BrokerClient<MioBrokerClientIo>,
+    mio_token: Option<mio::Token>,
 }
 
 #[derive(Debug)]
@@ -59,7 +60,10 @@ impl MioBrokerClient {
             write_buffer,
         };
         let inner = BrokerClient::new(io);
-        Self { inner }
+        Self {
+            inner,
+            mio_token: None,
+        }
     }
 
     fn poll(&mut self) -> anyhow::Result<()> {
@@ -104,6 +108,7 @@ impl WireguardBrokerMio for MioBrokerClient {
         registry: &mio::Registry,
         token: mio::Token,
     ) -> Result<(), Self::MioError> {
+        self.mio_token = Some(token);
         registry.register(
             &mut self.inner.io_mut().socket,
             token,
@@ -118,9 +123,14 @@ impl WireguardBrokerMio for MioBrokerClient {
     }
 
     fn unregister(&mut self, registry: &mio::Registry) -> Result<(), Self::MioError> {
+        self.mio_token = None;
         registry.deregister(&mut self.inner.io_mut().socket)?;
         Ok(())
     }
+
+    fn mio_token(&self) -> Option<mio::Token> {
+        self.mio_token
+    }
 }
 
 impl BrokerClientIo for MioBrokerClientIo {

wireguard-broker/src/brokers/native_unix.rs

@@ -16,7 +16,9 @@ const MAX_B64_KEY_SIZE: usize = WG_KEY_LEN * 5 / 3;
 const MAX_B64_PEER_ID_SIZE: usize = WG_PEER_LEN * 5 / 3;
 
 #[derive(Debug)]
-pub struct NativeUnixBroker {}
+pub struct NativeUnixBroker {
+    mio_token: Option<mio::Token>,
+}
 
 impl Default for NativeUnixBroker {
     fn default() -> Self {
@@ -26,7 +28,7 @@ impl Default for NativeUnixBroker {
 
 impl NativeUnixBroker {
     pub fn new() -> Self {
-        Self {}
+        Self { mio_token: None }
     }
 }
 
@@ -88,8 +90,9 @@ impl WireguardBrokerMio for NativeUnixBroker {
     fn register(
         &mut self,
         _registry: &mio::Registry,
-        _token: mio::Token,
+        token: mio::Token,
     ) -> Result<(), Self::MioError> {
+        self.mio_token = Some(token);
         Ok(())
     }
 
@@ -98,8 +101,13 @@ impl WireguardBrokerMio for NativeUnixBroker {
     }
 
     fn unregister(&mut self, _registry: &mio::Registry) -> Result<(), Self::MioError> {
+        self.mio_token = None;
         Ok(())
     }
+
+    fn mio_token(&self) -> Option<mio::Token> {
+        self.mio_token
+    }
 }
 
 #[derive(Debug, Builder)]

wireguard-broker/src/lib.rs

@@ -28,6 +28,8 @@ pub trait WireguardBrokerMio: WireGuardBroker {
         registry: &mio::Registry,
         token: mio::Token,
     ) -> Result<(), Self::MioError>;
+    fn mio_token(&self) -> Option<mio::Token>;
+
     /// Run after a mio::poll operation
     fn process_poll(&mut self) -> Result<(), Self::MioError>;