New grpclb implementation (#1558)

The new grpclb supports fallback to backends if remote balancer is unavailable

rpc_util.go

@@ -441,9 +441,7 @@ func recv(p *parser, c Codec, s *transport.Stream, dc Decompressor, m interface{
 }
 
 type rpcInfo struct {
-	failfast      bool
-	bytesSent     bool
-	bytesReceived bool
+	failfast bool
 }
 
 type rpcInfoContextKey struct{}
@@ -457,14 +455,6 @@ func rpcInfoFromContext(ctx context.Context) (s *rpcInfo, ok bool) {
 	return
 }
 
-func updateRPCInfoInContext(ctx context.Context, s rpcInfo) {
-	if ss, ok := rpcInfoFromContext(ctx); ok {
-		ss.bytesReceived = s.bytesReceived
-		ss.bytesSent = s.bytesSent
-	}
-	return
-}
-
 // Code returns the error code for err if it was produced by the rpc system.
 // Otherwise, it returns codes.Unknown.
 //