Move spawning tasks from thread pools to Service's TaskManager for block importing (#5647)

Co-Authored-By: Pierre Krieger <pierre.krieger1708@gmail.com>

substrate/client/service/src/chain_ops.rs

@@ -56,12 +56,13 @@ impl<
 	TExecDisp: 'static + NativeExecutionDispatch,
 	TImpQu: 'static + ImportQueue<TBl>,
 	TRtApi: 'static + Send + Sync,
+	Self: Send + 'static,
 {
 	type Block = TBl;
 	type NativeDispatch = TExecDisp;
 
 	fn import_blocks(
-		self,
+		mut self,
 		input: impl Read + Seek + Send + 'static,
 		force: bool,
 	) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send>> {
@@ -98,9 +99,6 @@ impl<
 			}
 		}
 
-		let client = self.client;
-		let mut queue = self.import_queue;
-
 		let mut io_reader_input = IoReader(input);
 		let mut count = None::<u64>;
 		let mut read_block_count = 0;
@@ -114,6 +112,9 @@ impl<
 		// This makes it possible either to interleave other operations in-between the block imports,
 		// or to stop the operation completely.
 		let import = future::poll_fn(move |cx| {
+			let client = &self.client;
+			let queue = &mut self.import_queue;
+
 			// Start by reading the number of blocks if not done so already.
 			let count = match count {
 				Some(c) => c,
@@ -203,13 +204,12 @@ impl<
 		to: Option<NumberFor<TBl>>,
 		binary: bool
 	) -> Pin<Box<dyn Future<Output = Result<(), Error>>>> {
-		let client = self.client;
 		let mut block = from;
 
 		let last = match to {
 			Some(v) if v.is_zero() => One::one(),
 			Some(v) => v,
-			None => client.chain_info().best_number,
+			None => self.client.chain_info().best_number,
 		};
 
 		let mut wrote_header = false;
@@ -222,6 +222,8 @@ impl<
 		// This makes it possible either to interleave other operations in-between the block exports,
 		// or to stop the operation completely.
 		let export = future::poll_fn(move |cx| {
+			let client = &self.client;
+
 			if last < block {
 				return std::task::Poll::Ready(Err("Invalid block range specified".into()));
 			}