Added support for Haystack tracing

vendor/google.golang.org/grpc/call.go

@@ -19,7 +19,7 @@
 package grpc
 
 import (
-	"golang.org/x/net/context"
+	"context"
 )
 
 // Invoke sends the RPC request on the wire and returns after response is
@@ -40,7 +40,7 @@ func (cc *ClientConn) Invoke(ctx context.Context, method string, args, reply int
 func combine(o1 []CallOption, o2 []CallOption) []CallOption {
 	// we don't use append because o1 could have extra capacity whose
 	// elements would be overwritten, which could cause inadvertent
-	// sharing (and race connditions) between concurrent calls
+	// sharing (and race conditions) between concurrent calls
 	if len(o1) == 0 {
 		return o2
 	} else if len(o2) == 0 {
@@ -63,31 +63,12 @@ func Invoke(ctx context.Context, method string, args, reply interface{}, cc *Cli
 var unaryStreamDesc = &StreamDesc{ServerStreams: false, ClientStreams: false}
 
 func invoke(ctx context.Context, method string, req, reply interface{}, cc *ClientConn, opts ...CallOption) error {
-	// TODO: implement retries in clientStream and make this simply
-	// newClientStream, SendMsg, RecvMsg.
-	firstAttempt := true
-	for {
-		csInt, err := newClientStream(ctx, unaryStreamDesc, cc, method, opts...)
-		if err != nil {
-			return err
-		}
-		cs := csInt.(*clientStream)
-		if err := cs.SendMsg(req); err != nil {
-			if !cs.c.failFast && cs.attempt.s.Unprocessed() && firstAttempt {
-				// TODO: Add a field to header for grpc-transparent-retry-attempts
-				firstAttempt = false
-				continue
-			}
-			return err
-		}
-		if err := cs.RecvMsg(reply); err != nil {
-			if !cs.c.failFast && cs.attempt.s.Unprocessed() && firstAttempt {
-				// TODO: Add a field to header for grpc-transparent-retry-attempts
-				firstAttempt = false
-				continue
-			}
-			return err
-		}
-		return nil
+	cs, err := newClientStream(ctx, unaryStreamDesc, cc, method, opts...)
+	if err != nil {
+		return err
 	}
+	if err := cs.SendMsg(req); err != nil {
+		return err
+	}
+	return cs.RecvMsg(reply)
 }