A few fixes + introduced back pressure oneshot.

roadmap/implementers-guide/src/types/overseer-protocol.md

@@ -380,6 +380,13 @@ enum DisputeCoordinatorMessage {
         /// - The validator index (within the session of the candidate) of the validator casting the vote.
         /// - The signature of the validator casting the vote.
         statements: Vec<(DisputeStatement, ValidatorIndex, ValidatorSignature)>,
+
+        /// Inform the requester once we finished importing.
+        ///
+        /// This is, we either discarded the votes, just record them because we
+        /// casted our vote already or recovered availability for the candidate
+        /// successfully.
+        pending_confirmation: oneshot::Sender<()>,
     },
     /// Fetch a list of all active disputes that the co-ordinator is aware of.
     ActiveDisputes(ResponseChannel<Vec<(SessionIndex, CandidateHash)>>),
@@ -434,21 +441,22 @@ responsible of distributing explicit dispute statements.
 enum DisputeDistributionMessage {
 
   /// Tell dispute distribution to distribute an explicit dispute statement to
-  validators.
+  /// validators.
   SendDispute((ValidVote, InvalidVote)),
 
   /// Ask DisputeDistribution to get votes we don't know about.
   /// Fetched votes will be reported via `DisputeCoordinatorMessage::ImportStatements`
   FetchMissingVotes {
-    candiate_hash: CandidateHash,
+    candidate_hash: CandidateHash,
     session: SessionIndex,
-    knownVotes: Bitfield,
+    known_valid_votes: Bitfield,
+    known_invalid_votes: Bitfield,
     /// Optional validator to query from. `ValidatorIndex` as in the above
     referenced session.
     from_validator: Option<ValidatorIndex>,
   }
   /// Tell the subsystem that a candidate is not available. Dispute distribution
-  can punish peers distributing votes on unavailable hashes for example.
+  /// can punish peers distributing votes on unavailable hashes.
   ReportCandidateUnavailable(CandidateHash),
 }
 ```