Stream additional block metadata via plugin (#22023) (#22179)

* Stream additional block metadata through plugin
blockhash, block_height, block_time, rewards are streamed

(cherry picked from commit f14928a970)

Co-authored-by: Lijun Wang <83639177+lijunwangs@users.noreply.github.com>

accountsdb-plugin-manager/src/block_metadata_notifier_interface.rs

@@ -0,0 +1,20 @@
+use {
+    solana_runtime::bank::RewardInfo,
+    solana_sdk::{clock::UnixTimestamp, pubkey::Pubkey},
+    std::sync::{Arc, RwLock},
+};
+
+/// Interface for notifying block metadata changes
+pub trait BlockMetadataNotifier {
+    /// Notify the block metadata
+    fn notify_block_metadata(
+        &self,
+        slot: u64,
+        blockhash: &str,
+        rewards: &RwLock<Vec<(Pubkey, RewardInfo)>>,
+        block_time: Option<UnixTimestamp>,
+        block_height: Option<u64>,
+    );
+}
+
+pub type BlockMetadataNotifierLock = Arc<RwLock<dyn BlockMetadataNotifier + Sync + Send>>;