[VOL-4291] OfAgent changes for gRPC migration

Change-Id: I8da1db6df49d478ef24ec8f9bd719e9692f48a7f
diff --git a/vendor/github.com/uber/jaeger-client-go/thrift/response_helper.go b/vendor/github.com/uber/jaeger-client-go/thrift/response_helper.go
new file mode 100644
index 0000000..d884c6a
--- /dev/null
+++ b/vendor/github.com/uber/jaeger-client-go/thrift/response_helper.go
@@ -0,0 +1,94 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package thrift
+
+import (
+	"context"
+)
+
+// See https://godoc.org/context#WithValue on why do we need the unexported typedefs.
+type responseHelperKey struct{}
+
+// TResponseHelper defines a object with a set of helper functions that can be
+// retrieved from the context object passed into server handler functions.
+//
+// Use GetResponseHelper to retrieve the injected TResponseHelper implementation
+// from the context object.
+//
+// The zero value of TResponseHelper is valid with all helper functions being
+// no-op.
+type TResponseHelper struct {
+	// THeader related functions
+	*THeaderResponseHelper
+}
+
+// THeaderResponseHelper defines THeader related TResponseHelper functions.
+//
+// The zero value of *THeaderResponseHelper is valid with all helper functions
+// being no-op.
+type THeaderResponseHelper struct {
+	proto *THeaderProtocol
+}
+
+// NewTHeaderResponseHelper creates a new THeaderResponseHelper from the
+// underlying TProtocol.
+func NewTHeaderResponseHelper(proto TProtocol) *THeaderResponseHelper {
+	if hp, ok := proto.(*THeaderProtocol); ok {
+		return &THeaderResponseHelper{
+			proto: hp,
+		}
+	}
+	return nil
+}
+
+// SetHeader sets a response header.
+//
+// It's no-op if the underlying protocol/transport does not support THeader.
+func (h *THeaderResponseHelper) SetHeader(key, value string) {
+	if h != nil && h.proto != nil {
+		h.proto.SetWriteHeader(key, value)
+	}
+}
+
+// ClearHeaders clears all the response headers previously set.
+//
+// It's no-op if the underlying protocol/transport does not support THeader.
+func (h *THeaderResponseHelper) ClearHeaders() {
+	if h != nil && h.proto != nil {
+		h.proto.ClearWriteHeaders()
+	}
+}
+
+// GetResponseHelper retrieves the TResponseHelper implementation injected into
+// the context object.
+//
+// If no helper was found in the context object, a nop helper with ok == false
+// will be returned.
+func GetResponseHelper(ctx context.Context) (helper TResponseHelper, ok bool) {
+	if v := ctx.Value(responseHelperKey{}); v != nil {
+		helper, ok = v.(TResponseHelper)
+	}
+	return
+}
+
+// SetResponseHelper injects TResponseHelper into the context object.
+func SetResponseHelper(ctx context.Context, helper TResponseHelper) context.Context {
+	return context.WithValue(ctx, responseHelperKey{}, helper)
+}