Implement Signer Registration Round closing

Author: jpraynaud

mithril-aggregator/src/signer_registerer.rs

@@ -79,6 +79,9 @@ pub trait SignerRegistrationRoundOpener: Sync + Send {
         registration_epoch: Epoch,
         stake_distribution: StakeDistribution,
     ) -> Result<(), SignerRegistrationError>;
+
+    /// Close a signer registration round
+    async fn close_registration_round(&self) -> Result<(), SignerRegistrationError>;
 }
 
 /// Implementation of a [SignerRegisterer]
@@ -127,6 +130,13 @@ impl SignerRegistrationRoundOpener for MithrilSignerRegisterer {
 
         Ok(())
     }
+
+    async fn close_registration_round(&self) -> Result<(), SignerRegistrationError> {
+        let mut current_round = self.current_round.write().await;
+        *current_round = None;
+
+        Ok(())
+    }
 }
 
 #[async_trait]