Name things slightly better

Signed-off-by: Miek Gieben <miek@miek.nl>

plugin/traffic/grpc_lb.go

@@ -0,0 +1,16 @@
+package traffic
+
+import (
+	"github.com/miekg/dns"
+)
+
+// See https://github.com/grpc/grpc/blob/master/doc/service_config.md for the fields in this proto.
+// We encode it as json and return it in a TXT field.
+var lbTXT = `grpc_config=[{"serviceConfig":{"loadBalancingConfig":[{"eds_experimental":{"LrsLoadReportingServerName":"","Cluster": "xds"}}]}}]`
+
+func txt(z string) []dns.RR {
+	return []dns.RR{&dns.TXT{
+		Hdr: dns.RR_Header{Name: z, Rrtype: dns.TypeTXT, Class: dns.ClassINET, Ttl: 5},
+		Txt: []string{lbTXT},
+	}}
+}