diff --git a/vendor/google.golang.org/grpc/attributes/attributes.go b/vendor/google.golang.org/grpc/attributes/attributes.go
new file mode 100644
index 0000000..68ffc62
--- /dev/null
+++ b/vendor/google.golang.org/grpc/attributes/attributes.go
@@ -0,0 +1,70 @@
+/*
+ *
+ * Copyright 2019 gRPC authors.
+ *
+ * Licensed 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 attributes defines a generic key/value store used in various gRPC
+// components.
+//
+// All APIs in this package are EXPERIMENTAL.
+package attributes
+
+import "fmt"
+
+// Attributes is an immutable struct for storing and retrieving generic
+// key/value pairs.  Keys must be hashable, and users should define their own
+// types for keys.
+type Attributes struct {
+	m map[interface{}]interface{}
+}
+
+// New returns a new Attributes containing all key/value pairs in kvs.  If the
+// same key appears multiple times, the last value overwrites all previous
+// values for that key.  Panics if len(kvs) is not even.
+func New(kvs ...interface{}) *Attributes {
+	if len(kvs)%2 != 0 {
+		panic(fmt.Sprintf("attributes.New called with unexpected input: len(kvs) = %v", len(kvs)))
+	}
+	a := &Attributes{m: make(map[interface{}]interface{}, len(kvs)/2)}
+	for i := 0; i < len(kvs)/2; i++ {
+		a.m[kvs[i*2]] = kvs[i*2+1]
+	}
+	return a
+}
+
+// WithValues returns a new Attributes containing all key/value pairs in a and
+// kvs.  Panics if len(kvs) is not even.  If the same key appears multiple
+// times, the last value overwrites all previous values for that key.  To
+// remove an existing key, use a nil value.
+func (a *Attributes) WithValues(kvs ...interface{}) *Attributes {
+	if len(kvs)%2 != 0 {
+		panic(fmt.Sprintf("attributes.New called with unexpected input: len(kvs) = %v", len(kvs)))
+	}
+	n := &Attributes{m: make(map[interface{}]interface{}, len(a.m)+len(kvs)/2)}
+	for k, v := range a.m {
+		n.m[k] = v
+	}
+	for i := 0; i < len(kvs)/2; i++ {
+		n.m[kvs[i*2]] = kvs[i*2+1]
+	}
+	return n
+}
+
+// Value returns the value associated with these attributes for key, or nil if
+// no value is associated with key.
+func (a *Attributes) Value(key interface{}) interface{} {
+	return a.m[key]
+}