Network sync refactoring (part 6) (#11940)

* Extract `NetworkKVProvider` trait in `sc-authority-discovery` and remove unnecessary dependency

* Extract `NetworkSyncForkRequest` trait in `sc-finality-grandpa`

* Relax requirements on `SyncOracle` trait, remove extra native methods from `NetworkService` that are already provided by trait impls

* Move `NetworkSigner` trait from `sc-authority-discovery` into `sc-network-common` and de-duplicate methods on `NetworkService`

* Move `NetworkKVProvider` trait from `sc-authority-discovery` into `sc-network-common` and de-duplicate methods on `NetworkService`

* Minimize `sc-authority-discovery` dependency on `sc-network`

* Move `NetworkSyncForkRequest` trait from `sc-finality-grandpa` to `sc-network-common` and de-duplicate methods in `NetworkService`

* Extract `NetworkStatusProvider` trait and de-duplicate methods on `NetworkService`

* Extract `NetworkPeers` trait and de-duplicate methods on `NetworkService`

* Extract `NetworkEventStream` trait and de-duplicate methods on `NetworkService`

* Move more methods from `NetworkService` into `NetworkPeers` trait

* Move `NetworkStateInfo` trait into `sc-network-common`

* Extract `NetworkNotification` trait and de-duplicate methods on `NetworkService`

* Extract `NetworkRequest` trait and de-duplicate methods on `NetworkService`

* Remove `NetworkService::local_peer_id()`, it is already provided by `NetworkStateInfo` impl

* Extract `NetworkTransaction` trait and de-duplicate methods on `NetworkService`

* Extract `NetworkBlock` trait and de-duplicate methods on `NetworkService`

* Remove dependencies on `NetworkService` from most of the methods of `sc-service`

* Address simple review comments

substrate/client/network/src/request_responses.rs

@@ -50,7 +50,9 @@ use libp2p::{
 		NetworkBehaviourAction, PollParameters,
 	},
 };
-use sc_network_common::request_responses::{IncomingRequest, OutgoingResponse, ProtocolConfig};
+use sc_network_common::request_responses::{
+	IfDisconnected, IncomingRequest, OutgoingResponse, ProtocolConfig, RequestFailure,
+};
 use std::{
 	borrow::Cow,
 	collections::{hash_map::Entry, HashMap},
@@ -118,26 +120,6 @@ impl From<(Cow<'static, str>, RequestId)> for ProtocolRequestId {
 	}
 }
 
-/// When sending a request, what to do on a disconnected recipient.
-#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
-pub enum IfDisconnected {
-	/// Try to connect to the peer.
-	TryConnect,
-	/// Just fail if the destination is not yet connected.
-	ImmediateError,
-}
-
-/// Convenience functions for `IfDisconnected`.
-impl IfDisconnected {
-	/// Shall we connect to a disconnected peer?
-	pub fn should_connect(self) -> bool {
-		match self {
-			Self::TryConnect => true,
-			Self::ImmediateError => false,
-		}
-	}
-}
-
 /// Implementation of `NetworkBehaviour` that provides support for request-response protocols.
 pub struct RequestResponsesBehaviour {
 	/// The multiple sub-protocols, by name.
@@ -787,23 +769,6 @@ pub enum RegisterError {
 	DuplicateProtocol(Cow<'static, str>),
 }
 
-/// Error in a request.
-#[derive(Debug, thiserror::Error)]
-#[allow(missing_docs)]
-pub enum RequestFailure {
-	#[error("We are not currently connected to the requested peer.")]
-	NotConnected,
-	#[error("Given protocol hasn't been registered.")]
-	UnknownProtocol,
-	#[error("Remote has closed the substream before answering, thereby signaling that it considers the request as valid, but refused to answer it.")]
-	Refused,
-	#[error("The remote replied, but the local node is no longer interested in the response.")]
-	Obsolete,
-	/// Problem on the network.
-	#[error("Problem on the network: {0}")]
-	Network(OutboundFailure),
-}
-
 /// Error when processing a request sent by a remote.
 #[derive(Debug, thiserror::Error)]
 pub enum ResponseFailure {