diff --git a/vendor/google.golang.org/grpc/encoding/encoding.go b/vendor/google.golang.org/grpc/encoding/encoding.go
new file mode 100644
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+++ b/vendor/google.golang.org/grpc/encoding/encoding.go
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+/*
+ *
+ * Copyright 2017 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 encoding defines the interface for the compressor and codec, and
+// functions to register and retrieve compressors and codecs.
+//
+// This package is EXPERIMENTAL.
+package encoding
+
+import (
+	"io"
+	"strings"
+)
+
+// Identity specifies the optional encoding for uncompressed streams.
+// It is intended for grpc internal use only.
+const Identity = "identity"
+
+// Compressor is used for compressing and decompressing when sending or
+// receiving messages.
+type Compressor interface {
+	// Compress writes the data written to wc to w after compressing it.  If an
+	// error occurs while initializing the compressor, that error is returned
+	// instead.
+	Compress(w io.Writer) (io.WriteCloser, error)
+	// Decompress reads data from r, decompresses it, and provides the
+	// uncompressed data via the returned io.Reader.  If an error occurs while
+	// initializing the decompressor, that error is returned instead.
+	Decompress(r io.Reader) (io.Reader, error)
+	// Name is the name of the compression codec and is used to set the content
+	// coding header.  The result must be static; the result cannot change
+	// between calls.
+	Name() string
+}
+
+var registeredCompressor = make(map[string]Compressor)
+
+// RegisterCompressor registers the compressor with gRPC by its name.  It can
+// be activated when sending an RPC via grpc.UseCompressor().  It will be
+// automatically accessed when receiving a message based on the content coding
+// header.  Servers also use it to send a response with the same encoding as
+// the request.
+//
+// NOTE: this function must only be called during initialization time (i.e. in
+// an init() function), and is not thread-safe.  If multiple Compressors are
+// registered with the same name, the one registered last will take effect.
+func RegisterCompressor(c Compressor) {
+	registeredCompressor[c.Name()] = c
+}
+
+// GetCompressor returns Compressor for the given compressor name.
+func GetCompressor(name string) Compressor {
+	return registeredCompressor[name]
+}
+
+// Codec defines the interface gRPC uses to encode and decode messages.  Note
+// that implementations of this interface must be thread safe; a Codec's
+// methods can be called from concurrent goroutines.
+type Codec interface {
+	// Marshal returns the wire format of v.
+	Marshal(v interface{}) ([]byte, error)
+	// Unmarshal parses the wire format into v.
+	Unmarshal(data []byte, v interface{}) error
+	// Name returns the name of the Codec implementation. The returned string
+	// will be used as part of content type in transmission.  The result must be
+	// static; the result cannot change between calls.
+	Name() string
+}
+
+var registeredCodecs = make(map[string]Codec)
+
+// RegisterCodec registers the provided Codec for use with all gRPC clients and
+// servers.
+//
+// The Codec will be stored and looked up by result of its Name() method, which
+// should match the content-subtype of the encoding handled by the Codec.  This
+// is case-insensitive, and is stored and looked up as lowercase.  If the
+// result of calling Name() is an empty string, RegisterCodec will panic. See
+// Content-Type on
+// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for
+// more details.
+//
+// NOTE: this function must only be called during initialization time (i.e. in
+// an init() function), and is not thread-safe.  If multiple Compressors are
+// registered with the same name, the one registered last will take effect.
+func RegisterCodec(codec Codec) {
+	if codec == nil {
+		panic("cannot register a nil Codec")
+	}
+	if codec.Name() == "" {
+		panic("cannot register Codec with empty string result for Name()")
+	}
+	contentSubtype := strings.ToLower(codec.Name())
+	registeredCodecs[contentSubtype] = codec
+}
+
+// GetCodec gets a registered Codec by content-subtype, or nil if no Codec is
+// registered for the content-subtype.
+//
+// The content-subtype is expected to be lowercase.
+func GetCodec(contentSubtype string) Codec {
+	return registeredCodecs[contentSubtype]
+}