split NetworkBridge into two subsystems (#5616)

* foo

* rolling session window

* fixup

* remove use statemetn

* fmt

* split NetworkBridge into two subsystems

Pending cleanup

* split

* chore: reexport OrchestraError as OverseerError

* chore: silence warnings

* fixup tests

* chore: add default timenout of 30s to subsystem test helper ctx handle

* single item channel

* fixins

* fmt

* cleanup

* remove dead code

* remove sync bounds again

* wire up shared state

* deal with some FIXMEs

* use distinct tags

Co-authored-by: Andrei Sandu <54316454+sandreim@users.noreply.github.com>

* use tag

Co-authored-by: Andrei Sandu <54316454+sandreim@users.noreply.github.com>

* address naming

tx and rx are common in networking and also have an implicit meaning regarding networking
compared to incoming and outgoing which are already used with subsystems themselvesq

* remove unused sync oracle

* remove unneeded state

* fix tests

* chore: fmt

* do not try to register twice

* leak Metrics type

Co-authored-by: Andrei Sandu <54316454+sandreim@users.noreply.github.com>
Co-authored-by: Andronik <write@reusable.software>

polkadot/node/subsystem-util/src/rolling_session_window.rs

@@ -28,16 +28,18 @@ use polkadot_node_subsystem::{
 	messages::{RuntimeApiMessage, RuntimeApiRequest},
 	overseer,
 };
-use thiserror::Error;
 
 /// Sessions unavailable in state to cache.
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, thiserror::Error)]
 pub enum SessionsUnavailableReason {
 	/// Runtime API subsystem was unavailable.
-	RuntimeApiUnavailable(oneshot::Canceled),
+	#[error(transparent)]
+	RuntimeApiUnavailable(#[from] oneshot::Canceled),
 	/// The runtime API itself returned an error.
-	RuntimeApi(RuntimeApiError),
+	#[error(transparent)]
+	RuntimeApi(#[from] RuntimeApiError),
 	/// Missing session info from runtime API for given `SessionIndex`.
+	#[error("Missing session index {0:?}")]
 	Missing(SessionIndex),
 }
 
@@ -53,20 +55,16 @@ pub struct SessionsUnavailableInfo {
 }
 
 /// Sessions were unavailable to fetch from the state for some reason.
-#[derive(Debug, Error, Clone)]
+#[derive(Debug, thiserror::Error, Clone)]
+#[error("Sessions unavailable: {kind:?}, info: {info:?}")]
 pub struct SessionsUnavailable {
 	/// The error kind.
+	#[source]
 	kind: SessionsUnavailableReason,
 	/// The info about the session window, if any.
 	info: Option<SessionsUnavailableInfo>,
 }
 
-impl core::fmt::Display for SessionsUnavailable {
-	fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
-		write!(f, "Sessions unavailable: {:?}, info: {:?}", self.kind, self.info)
-	}
-}
-
 /// An indicated update of the rolling session window.
 #[derive(Debug, PartialEq, Clone)]
 pub enum SessionWindowUpdate {