Improve statement-store gossiping performance (paritytech#9912)

# Description

Fixes gossiping and scalability issues in the statement-store
networking.

1. Reduced gossiping traffic by propagating only recent statements
instead of all.
2. Added an early check for statements that the node already has to skip
duplicate processing.
3. Added splitting of large statement batches to stay under
MAX_STATEMENT_NOTIFICATION_SIZE; oversized individual statements are
skipped.
4. MAX_STATEMENT_NOTIFICATION_SIZE was updated to the commonly used 1MB,
which drastically improved the gossiping speed.
5. Notifications are sent asynchronously. I don't see much difference in
performance, but according to @lexnv, it's better to do:
paritytech#9296.
6. Added a 10s timeout to handle very slow or disconnected peers.

## Integration

Internal optimizations to the gossip protocol. No downstream changes
required.

Related PR: paritytech#9965

## Things to handle in further PRs
- After this PR, nodes don't send all statements to new peers anymore,
only the recent ones.
- After restarting, the node doesn't re-gossip statements it wasn't
gossiped.
- Broadcasting notifications to all peers when the first peer is slow is
limited. We could instead use a FuturesUnordered.

---------

Co-authored-by: cmd[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Bastian Köcher <[email protected]>

Author: 3 people

Cargo.lock

@@ -0,0 +1,14 @@
+title: '[WIP] Fix statement-store gossiping'
+doc:
+- audience: Node Dev
+  description: |-
+    Fixes gossiping and scalability issues in the statement-store networking:
+    reduces traffic by propagating only recent statements, skips duplicate processing,
+    and splits large batches to stay under MAX_STATEMENT_NOTIFICATION_SIZE.
+crates:
+- name: sc-network-statement
+  bump: minor
+- name: sc-statement-store
+  bump: minor
+- name: sp-statement-store
+  bump: minor

prdoc/pr_9912.prdoc

@@ -29,3 +29,7 @@ sc-network-types = { workspace = true, default-features = true }
 sp-consensus = { workspace = true, default-features = true }
 sp-runtime = { workspace = true, default-features = true }
 sp-statement-store = { workspace = true, default-features = true }
+tokio = { workspace = true }
+
+[dev-dependencies]
+async-trait = { workspace = true }

substrate/client/network/statement/Cargo.toml

@@ -24,10 +24,10 @@ use std::time;
 pub(crate) const PROPAGATE_TIMEOUT: time::Duration = time::Duration::from_millis(1000);
 
 /// Maximum number of known statement hashes to keep for a peer.
-pub(crate) const MAX_KNOWN_STATEMENTS: usize = 4 * 1024 * 1024;
+pub(crate) const MAX_KNOWN_STATEMENTS: usize = 4 * 1024 * 1024; // * 32 bytes for hash = 128 MB per peer
 
 /// Maximum allowed size for a statement notification.
-pub(crate) const MAX_STATEMENT_SIZE: u64 = 256 * 1024;
+pub(crate) const MAX_STATEMENT_NOTIFICATION_SIZE: u64 = 1024 * 1024;
 
 /// Maximum number of statement validation request we keep at any moment.
 pub(crate) const MAX_PENDING_STATEMENTS: usize = 2 * 1024 * 1024;