Reduce network bandwidth, improve parablock times: optimize approval-distribution

node/core/approval-voting/src/import.rs

@@ -574,6 +574,7 @@ pub(crate) async fn handle_new_head(
 			parent_hash: block_header.parent_hash,
 			candidates: included_candidates.iter().map(|(hash, _, _, _)| *hash).collect(),
 			slot,
+			session: session_index,
 		});
 
 		imported_candidates.push(BlockImportedCandidates {

node/core/approval-voting/src/lib.rs

@@ -1006,6 +1006,7 @@ fn distribution_messages_for_activation(
 			parent_hash: block_entry.parent_hash(),
 			candidates: block_entry.candidates().iter().map(|(_, c_hash)| *c_hash).collect(),
 			slot: block_entry.slot(),
+			session: block_entry.session(),
 		});
 
 		for (i, (_, candidate_hash)) in block_entry.candidates().iter().enumerate() {

node/network/approval-distribution/Cargo.toml

@@ -10,11 +10,13 @@ polkadot-node-network-protocol = { path = "../protocol" }
 polkadot-node-subsystem = { path = "../../subsystem" }
 polkadot-node-subsystem-util = { path = "../../subsystem-util" }
 polkadot-primitives = { path = "../../../primitives" }
+rand = "0.8"
 
 futures = "0.3.21"
 gum = { package = "tracing-gum", path = "../../gum" }
 
 [dev-dependencies]
+sp-authority-discovery = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "master", features = ["std"] }
 
 polkadot-node-subsystem-util = { path = "../../subsystem-util" }
@@ -23,5 +25,6 @@ polkadot-node-subsystem-test-helpers = { path = "../../subsystem-test-helpers" }
 assert_matches = "1.4.0"
 schnorrkel = { version = "0.9.1", default-features = false }
 rand_core = "0.5.1" # should match schnorrkel
+rand_chacha = "0.3.1"
 env_logger = "0.9.0"
 log = "0.4.16"