2871 remove proposalHeartbeat infrastructure (#2874)

* 2871 remove proposalHeartbeat infrastructure

* 2871 add preliminary changelog entry

docs/spec/reactors/consensus/consensus-reactor.md

@@ -338,12 +338,11 @@ BlockID has seen +2/3 votes. This routine is based on the local RoundState (`rs`
 
 ## Broadcast routine
 
-The Broadcast routine subscribes to an internal event bus to receive new round steps, votes messages and proposal
-heartbeat messages, and broadcasts messages to peers upon receiving those events.
+The Broadcast routine subscribes to an internal event bus to receive new round steps and votes messages, and broadcasts messages to peers upon receiving those 
+events.
 It broadcasts `NewRoundStepMessage` or `CommitStepMessage` upon new round state event. Note that
 broadcasting these messages does not depend on the PeerRoundState; it is sent on the StateChannel.
 Upon receiving VoteMessage it broadcasts `HasVoteMessage` message to its peers on the StateChannel.
-`ProposalHeartbeatMessage` is sent the same way on the StateChannel.
 
 ## Channels
 

docs/spec/reactors/consensus/consensus.md

@@ -89,33 +89,6 @@ type BlockPartMessage struct {
 }
 ```
 
-## ProposalHeartbeatMessage
-
-ProposalHeartbeatMessage is sent to signal that a node is alive and waiting for transactions
-to be able to create a next block proposal.
-
-```go
-type ProposalHeartbeatMessage struct {
-    Heartbeat Heartbeat
-}
-```
-
-### Heartbeat
-
-Heartbeat contains validator information (address and index),
-height, round and sequence number. It is signed by the private key of the validator.
-
-```go
-type Heartbeat struct {
-    ValidatorAddress []byte
-    ValidatorIndex   int
-    Height           int64
-    Round            int
-    Sequence         int
-    Signature        Signature
-}
-```
-
 ## NewRoundStepMessage
 
 NewRoundStepMessage is sent for every step transition during the core consensus algorithm execution.