RpcHandlers Refactorings (#6846)

* allow access to the underlying Pubsub instance from RpcHandlers

* bump Cargo.lock

* no more Arc<RpcHandlers>

* bump Cargo.lock

* Debug,.

* Arc<RpcHandlers>

* RpcHandler

* RpcHandlers::io_handler

* remove chain spec from cli

* address pr comments

* remove stray newline

Co-authored-by: Ashley <ashley.ruglys@gmail.com>

Co-authored-by: Tomasz Drwięga <tomasz@parity.io>
Co-authored-by: Ashley <ashley.ruglys@gmail.com>

substrate/client/service/src/lib.rs

@@ -96,7 +96,8 @@ impl<T: MallocSizeOf> MallocSizeOfWasm for T {}
 impl<T> MallocSizeOfWasm for T {}
 
 /// RPC handlers that can perform RPC queries.
-pub struct RpcHandlers(sc_rpc_server::RpcHandler<sc_rpc::Metadata>);
+#[derive(Clone)]
+pub struct RpcHandlers(Arc<jsonrpc_core::MetaIoHandler<sc_rpc::Metadata>>);
 
 impl RpcHandlers {
 	/// Starts an RPC query.
@@ -115,6 +116,11 @@ impl RpcHandlers {
 			.map(|res| res.expect("this should never fail"))
 			.boxed()
 	}
+
+	/// Provides access to the underlying `MetaIoHandler`
+	pub fn io_handler(&self) -> Arc<jsonrpc_core::MetaIoHandler<sc_rpc::Metadata>> {
+		self.0.clone()
+	}
 }
 
 /// Sinks to propagate network status updates.