style(bitswap/message) rename struct

so there's one less name to think about

exchange/bitswap/message/message.go

@@ -27,13 +27,13 @@ type Exportable interface {
 }
 
 // message wraps a proto message for convenience
-type message struct {
+type impl struct {
 	wantlist map[u.Key]struct{}
 	blocks   []blocks.Block
 }
 
 func New() BitSwapMessage {
-	return &message{
+	return &impl{
 		wantlist: make(map[u.Key]struct{}),
 	}
 }
@@ -51,7 +51,7 @@ func newMessageFromProto(pbm pb.Message) BitSwapMessage {
 }
 
 // TODO(brian): convert these into keys
-func (m *message) Wantlist() []u.Key {
+func (m *impl) Wantlist() []u.Key {
 	wl := make([]u.Key, 0)
 	for k, _ := range m.wantlist {
 		wl = append(wl, k)
@@ -60,15 +60,15 @@ func (m *message) Wantlist() []u.Key {
 }
 
 // TODO(brian): convert these into blocks
-func (m *message) Blocks() []blocks.Block {
+func (m *impl) Blocks() []blocks.Block {
 	return m.blocks
 }
 
-func (m *message) AddWanted(k u.Key) {
+func (m *impl) AddWanted(k u.Key) {
 	m.wantlist[k] = struct{}{}
 }
 
-func (m *message) AppendBlock(b blocks.Block) {
+func (m *impl) AppendBlock(b blocks.Block) {
 	m.blocks = append(m.blocks, b)
 }
 
@@ -81,7 +81,7 @@ func FromNet(nmsg netmsg.NetMessage) (BitSwapMessage, error) {
 	return m, nil
 }
 
-func (m *message) ToProto() *pb.Message {
+func (m *impl) ToProto() *pb.Message {
 	pb := new(pb.Message)
 	for _, k := range m.Wantlist() {
 		pb.Wantlist = append(pb.Wantlist, string(k))
@@ -92,6 +92,6 @@ func (m *message) ToProto() *pb.Message {
 	return pb
 }
 
-func (m *message) ToNet(p peer.Peer) (nm.NetMessage, error) {
+func (m *impl) ToNet(p peer.Peer) (nm.NetMessage, error) {
 	return nm.FromObject(p, m.ToProto())
 }