Faster piece getting via RPC

crates/subspace-farmer/src/farmer_cache.rs

@@ -531,7 +531,7 @@ where
             debug!(%segment_index, "Downloading potentially useful pieces");
 
             // We do not insert pieces into cache/heap yet, so we don't know if all of these pieces
-            // will be included, but there is a good chance they will be and we want to acknowledge
+            // will be included, but there is a good chance they will be, and we want to acknowledge
             // new segment header as soon as possible
             let pieces_to_maybe_include = segment_index
                 .segment_piece_indexes()

crates/subspace-farmer/src/node_client/node_rpc_client.rs

@@ -234,10 +234,15 @@ impl NodeClient for NodeRpcClient {
     }
 
     async fn piece(&self, piece_index: PieceIndex) -> Result<Option<Piece>, RpcError> {
-        Ok(self
-            .client
-            .request("subspace_piece", rpc_params![&piece_index])
-            .await?)
+        let client = Arc::clone(&self.client);
+        // Spawn a separate task to improve concurrency due to slow-ish JSON decoding that causes
+        // issues for jsonrpsee
+        let piece_fut = tokio::task::spawn(async move {
+            client
+                .request("subspace_piece", rpc_params![&piece_index])
+                .await
+        });
+        Ok(piece_fut.await??)
     }
 
     async fn acknowledge_archived_segment_header(