Update some comments

consensus/mod.go

@@ -11,6 +11,7 @@ import (
 type Proposal interface {
 	encoding.Packable
 
+	// GetIndex returns the index of the proposal from the first one.
 	GetIndex() uint64
 
 	// GetHash returns the hash of the proposal.
@@ -49,10 +50,11 @@ type ChainFactory interface {
 
 // Actor is the primitive to send proposals to a consensus implementation.
 type Actor interface {
-	// Propose performs the consensus algorithm using the list of nodes
-	// as participants.
+	// Propose performs the consensus algorithm. The list of participants is
+	// left to the implementation.
 	Propose(proposal Proposal) error
 
+	// Close must clean the resources of the actor.
 	Close() error
 }
 

cosi/threshold/signature.go

@@ -209,5 +209,6 @@ func (f verifierFactory) FromAuthority(authority crypto.CollectiveAuthority) (cr
 }
 
 func (f verifierFactory) FromArray([]crypto.PublicKey) (crypto.Verifier, error) {
+	// TODO: think about this
 	return nil, xerrors.New("not implemented")
 }

ledger/byzcoin/mod.go

@@ -30,6 +30,8 @@ const (
 )
 
 var (
+	// AuthorityKey is a reserved instance key for the roster of the chain. It
+	// may evolve after each block.
 	authorityKey = []byte{0x01}
 )