diff --git a/vendor/google.golang.org/protobuf/encoding/protowire/wire.go b/vendor/google.golang.org/protobuf/encoding/protowire/wire.go
new file mode 100644
index 0000000..a427f8b
--- /dev/null
+++ b/vendor/google.golang.org/protobuf/encoding/protowire/wire.go
@@ -0,0 +1,538 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package protowire parses and formats the raw wire encoding.
+// See https://developers.google.com/protocol-buffers/docs/encoding.
+//
+// For marshaling and unmarshaling entire protobuf messages,
+// use the "google.golang.org/protobuf/proto" package instead.
+package protowire
+
+import (
+	"io"
+	"math"
+	"math/bits"
+
+	"google.golang.org/protobuf/internal/errors"
+)
+
+// Number represents the field number.
+type Number int32
+
+const (
+	MinValidNumber      Number = 1
+	FirstReservedNumber Number = 19000
+	LastReservedNumber  Number = 19999
+	MaxValidNumber      Number = 1<<29 - 1
+)
+
+// IsValid reports whether the field number is semantically valid.
+//
+// Note that while numbers within the reserved range are semantically invalid,
+// they are syntactically valid in the wire format.
+// Implementations may treat records with reserved field numbers as unknown.
+func (n Number) IsValid() bool {
+	return MinValidNumber <= n && n < FirstReservedNumber || LastReservedNumber < n && n <= MaxValidNumber
+}
+
+// Type represents the wire type.
+type Type int8
+
+const (
+	VarintType     Type = 0
+	Fixed32Type    Type = 5
+	Fixed64Type    Type = 1
+	BytesType      Type = 2
+	StartGroupType Type = 3
+	EndGroupType   Type = 4
+)
+
+const (
+	_ = -iota
+	errCodeTruncated
+	errCodeFieldNumber
+	errCodeOverflow
+	errCodeReserved
+	errCodeEndGroup
+)
+
+var (
+	errFieldNumber = errors.New("invalid field number")
+	errOverflow    = errors.New("variable length integer overflow")
+	errReserved    = errors.New("cannot parse reserved wire type")
+	errEndGroup    = errors.New("mismatching end group marker")
+	errParse       = errors.New("parse error")
+)
+
+// ParseError converts an error code into an error value.
+// This returns nil if n is a non-negative number.
+func ParseError(n int) error {
+	if n >= 0 {
+		return nil
+	}
+	switch n {
+	case errCodeTruncated:
+		return io.ErrUnexpectedEOF
+	case errCodeFieldNumber:
+		return errFieldNumber
+	case errCodeOverflow:
+		return errOverflow
+	case errCodeReserved:
+		return errReserved
+	case errCodeEndGroup:
+		return errEndGroup
+	default:
+		return errParse
+	}
+}
+
+// ConsumeField parses an entire field record (both tag and value) and returns
+// the field number, the wire type, and the total length.
+// This returns a negative length upon an error (see ParseError).
+//
+// The total length includes the tag header and the end group marker (if the
+// field is a group).
+func ConsumeField(b []byte) (Number, Type, int) {
+	num, typ, n := ConsumeTag(b)
+	if n < 0 {
+		return 0, 0, n // forward error code
+	}
+	m := ConsumeFieldValue(num, typ, b[n:])
+	if m < 0 {
+		return 0, 0, m // forward error code
+	}
+	return num, typ, n + m
+}
+
+// ConsumeFieldValue parses a field value and returns its length.
+// This assumes that the field Number and wire Type have already been parsed.
+// This returns a negative length upon an error (see ParseError).
+//
+// When parsing a group, the length includes the end group marker and
+// the end group is verified to match the starting field number.
+func ConsumeFieldValue(num Number, typ Type, b []byte) (n int) {
+	switch typ {
+	case VarintType:
+		_, n = ConsumeVarint(b)
+		return n
+	case Fixed32Type:
+		_, n = ConsumeFixed32(b)
+		return n
+	case Fixed64Type:
+		_, n = ConsumeFixed64(b)
+		return n
+	case BytesType:
+		_, n = ConsumeBytes(b)
+		return n
+	case StartGroupType:
+		n0 := len(b)
+		for {
+			num2, typ2, n := ConsumeTag(b)
+			if n < 0 {
+				return n // forward error code
+			}
+			b = b[n:]
+			if typ2 == EndGroupType {
+				if num != num2 {
+					return errCodeEndGroup
+				}
+				return n0 - len(b)
+			}
+
+			n = ConsumeFieldValue(num2, typ2, b)
+			if n < 0 {
+				return n // forward error code
+			}
+			b = b[n:]
+		}
+	case EndGroupType:
+		return errCodeEndGroup
+	default:
+		return errCodeReserved
+	}
+}
+
+// AppendTag encodes num and typ as a varint-encoded tag and appends it to b.
+func AppendTag(b []byte, num Number, typ Type) []byte {
+	return AppendVarint(b, EncodeTag(num, typ))
+}
+
+// ConsumeTag parses b as a varint-encoded tag, reporting its length.
+// This returns a negative length upon an error (see ParseError).
+func ConsumeTag(b []byte) (Number, Type, int) {
+	v, n := ConsumeVarint(b)
+	if n < 0 {
+		return 0, 0, n // forward error code
+	}
+	num, typ := DecodeTag(v)
+	if num < MinValidNumber {
+		return 0, 0, errCodeFieldNumber
+	}
+	return num, typ, n
+}
+
+func SizeTag(num Number) int {
+	return SizeVarint(EncodeTag(num, 0)) // wire type has no effect on size
+}
+
+// AppendVarint appends v to b as a varint-encoded uint64.
+func AppendVarint(b []byte, v uint64) []byte {
+	switch {
+	case v < 1<<7:
+		b = append(b, byte(v))
+	case v < 1<<14:
+		b = append(b,
+			byte((v>>0)&0x7f|0x80),
+			byte(v>>7))
+	case v < 1<<21:
+		b = append(b,
+			byte((v>>0)&0x7f|0x80),
+			byte((v>>7)&0x7f|0x80),
+			byte(v>>14))
+	case v < 1<<28:
+		b = append(b,
+			byte((v>>0)&0x7f|0x80),
+			byte((v>>7)&0x7f|0x80),
+			byte((v>>14)&0x7f|0x80),
+			byte(v>>21))
+	case v < 1<<35:
+		b = append(b,
+			byte((v>>0)&0x7f|0x80),
+			byte((v>>7)&0x7f|0x80),
+			byte((v>>14)&0x7f|0x80),
+			byte((v>>21)&0x7f|0x80),
+			byte(v>>28))
+	case v < 1<<42:
+		b = append(b,
+			byte((v>>0)&0x7f|0x80),
+			byte((v>>7)&0x7f|0x80),
+			byte((v>>14)&0x7f|0x80),
+			byte((v>>21)&0x7f|0x80),
+			byte((v>>28)&0x7f|0x80),
+			byte(v>>35))
+	case v < 1<<49:
+		b = append(b,
+			byte((v>>0)&0x7f|0x80),
+			byte((v>>7)&0x7f|0x80),
+			byte((v>>14)&0x7f|0x80),
+			byte((v>>21)&0x7f|0x80),
+			byte((v>>28)&0x7f|0x80),
+			byte((v>>35)&0x7f|0x80),
+			byte(v>>42))
+	case v < 1<<56:
+		b = append(b,
+			byte((v>>0)&0x7f|0x80),
+			byte((v>>7)&0x7f|0x80),
+			byte((v>>14)&0x7f|0x80),
+			byte((v>>21)&0x7f|0x80),
+			byte((v>>28)&0x7f|0x80),
+			byte((v>>35)&0x7f|0x80),
+			byte((v>>42)&0x7f|0x80),
+			byte(v>>49))
+	case v < 1<<63:
+		b = append(b,
+			byte((v>>0)&0x7f|0x80),
+			byte((v>>7)&0x7f|0x80),
+			byte((v>>14)&0x7f|0x80),
+			byte((v>>21)&0x7f|0x80),
+			byte((v>>28)&0x7f|0x80),
+			byte((v>>35)&0x7f|0x80),
+			byte((v>>42)&0x7f|0x80),
+			byte((v>>49)&0x7f|0x80),
+			byte(v>>56))
+	default:
+		b = append(b,
+			byte((v>>0)&0x7f|0x80),
+			byte((v>>7)&0x7f|0x80),
+			byte((v>>14)&0x7f|0x80),
+			byte((v>>21)&0x7f|0x80),
+			byte((v>>28)&0x7f|0x80),
+			byte((v>>35)&0x7f|0x80),
+			byte((v>>42)&0x7f|0x80),
+			byte((v>>49)&0x7f|0x80),
+			byte((v>>56)&0x7f|0x80),
+			1)
+	}
+	return b
+}
+
+// ConsumeVarint parses b as a varint-encoded uint64, reporting its length.
+// This returns a negative length upon an error (see ParseError).
+func ConsumeVarint(b []byte) (v uint64, n int) {
+	var y uint64
+	if len(b) <= 0 {
+		return 0, errCodeTruncated
+	}
+	v = uint64(b[0])
+	if v < 0x80 {
+		return v, 1
+	}
+	v -= 0x80
+
+	if len(b) <= 1 {
+		return 0, errCodeTruncated
+	}
+	y = uint64(b[1])
+	v += y << 7
+	if y < 0x80 {
+		return v, 2
+	}
+	v -= 0x80 << 7
+
+	if len(b) <= 2 {
+		return 0, errCodeTruncated
+	}
+	y = uint64(b[2])
+	v += y << 14
+	if y < 0x80 {
+		return v, 3
+	}
+	v -= 0x80 << 14
+
+	if len(b) <= 3 {
+		return 0, errCodeTruncated
+	}
+	y = uint64(b[3])
+	v += y << 21
+	if y < 0x80 {
+		return v, 4
+	}
+	v -= 0x80 << 21
+
+	if len(b) <= 4 {
+		return 0, errCodeTruncated
+	}
+	y = uint64(b[4])
+	v += y << 28
+	if y < 0x80 {
+		return v, 5
+	}
+	v -= 0x80 << 28
+
+	if len(b) <= 5 {
+		return 0, errCodeTruncated
+	}
+	y = uint64(b[5])
+	v += y << 35
+	if y < 0x80 {
+		return v, 6
+	}
+	v -= 0x80 << 35
+
+	if len(b) <= 6 {
+		return 0, errCodeTruncated
+	}
+	y = uint64(b[6])
+	v += y << 42
+	if y < 0x80 {
+		return v, 7
+	}
+	v -= 0x80 << 42
+
+	if len(b) <= 7 {
+		return 0, errCodeTruncated
+	}
+	y = uint64(b[7])
+	v += y << 49
+	if y < 0x80 {
+		return v, 8
+	}
+	v -= 0x80 << 49
+
+	if len(b) <= 8 {
+		return 0, errCodeTruncated
+	}
+	y = uint64(b[8])
+	v += y << 56
+	if y < 0x80 {
+		return v, 9
+	}
+	v -= 0x80 << 56
+
+	if len(b) <= 9 {
+		return 0, errCodeTruncated
+	}
+	y = uint64(b[9])
+	v += y << 63
+	if y < 2 {
+		return v, 10
+	}
+	return 0, errCodeOverflow
+}
+
+// SizeVarint returns the encoded size of a varint.
+// The size is guaranteed to be within 1 and 10, inclusive.
+func SizeVarint(v uint64) int {
+	// This computes 1 + (bits.Len64(v)-1)/7.
+	// 9/64 is a good enough approximation of 1/7
+	return int(9*uint32(bits.Len64(v))+64) / 64
+}
+
+// AppendFixed32 appends v to b as a little-endian uint32.
+func AppendFixed32(b []byte, v uint32) []byte {
+	return append(b,
+		byte(v>>0),
+		byte(v>>8),
+		byte(v>>16),
+		byte(v>>24))
+}
+
+// ConsumeFixed32 parses b as a little-endian uint32, reporting its length.
+// This returns a negative length upon an error (see ParseError).
+func ConsumeFixed32(b []byte) (v uint32, n int) {
+	if len(b) < 4 {
+		return 0, errCodeTruncated
+	}
+	v = uint32(b[0])<<0 | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
+	return v, 4
+}
+
+// SizeFixed32 returns the encoded size of a fixed32; which is always 4.
+func SizeFixed32() int {
+	return 4
+}
+
+// AppendFixed64 appends v to b as a little-endian uint64.
+func AppendFixed64(b []byte, v uint64) []byte {
+	return append(b,
+		byte(v>>0),
+		byte(v>>8),
+		byte(v>>16),
+		byte(v>>24),
+		byte(v>>32),
+		byte(v>>40),
+		byte(v>>48),
+		byte(v>>56))
+}
+
+// ConsumeFixed64 parses b as a little-endian uint64, reporting its length.
+// This returns a negative length upon an error (see ParseError).
+func ConsumeFixed64(b []byte) (v uint64, n int) {
+	if len(b) < 8 {
+		return 0, errCodeTruncated
+	}
+	v = uint64(b[0])<<0 | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 | uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
+	return v, 8
+}
+
+// SizeFixed64 returns the encoded size of a fixed64; which is always 8.
+func SizeFixed64() int {
+	return 8
+}
+
+// AppendBytes appends v to b as a length-prefixed bytes value.
+func AppendBytes(b []byte, v []byte) []byte {
+	return append(AppendVarint(b, uint64(len(v))), v...)
+}
+
+// ConsumeBytes parses b as a length-prefixed bytes value, reporting its length.
+// This returns a negative length upon an error (see ParseError).
+func ConsumeBytes(b []byte) (v []byte, n int) {
+	m, n := ConsumeVarint(b)
+	if n < 0 {
+		return nil, n // forward error code
+	}
+	if m > uint64(len(b[n:])) {
+		return nil, errCodeTruncated
+	}
+	return b[n:][:m], n + int(m)
+}
+
+// SizeBytes returns the encoded size of a length-prefixed bytes value,
+// given only the length.
+func SizeBytes(n int) int {
+	return SizeVarint(uint64(n)) + n
+}
+
+// AppendString appends v to b as a length-prefixed bytes value.
+func AppendString(b []byte, v string) []byte {
+	return append(AppendVarint(b, uint64(len(v))), v...)
+}
+
+// ConsumeString parses b as a length-prefixed bytes value, reporting its length.
+// This returns a negative length upon an error (see ParseError).
+func ConsumeString(b []byte) (v string, n int) {
+	bb, n := ConsumeBytes(b)
+	return string(bb), n
+}
+
+// AppendGroup appends v to b as group value, with a trailing end group marker.
+// The value v must not contain the end marker.
+func AppendGroup(b []byte, num Number, v []byte) []byte {
+	return AppendVarint(append(b, v...), EncodeTag(num, EndGroupType))
+}
+
+// ConsumeGroup parses b as a group value until the trailing end group marker,
+// and verifies that the end marker matches the provided num. The value v
+// does not contain the end marker, while the length does contain the end marker.
+// This returns a negative length upon an error (see ParseError).
+func ConsumeGroup(num Number, b []byte) (v []byte, n int) {
+	n = ConsumeFieldValue(num, StartGroupType, b)
+	if n < 0 {
+		return nil, n // forward error code
+	}
+	b = b[:n]
+
+	// Truncate off end group marker, but need to handle denormalized varints.
+	// Assuming end marker is never 0 (which is always the case since
+	// EndGroupType is non-zero), we can truncate all trailing bytes where the
+	// lower 7 bits are all zero (implying that the varint is denormalized).
+	for len(b) > 0 && b[len(b)-1]&0x7f == 0 {
+		b = b[:len(b)-1]
+	}
+	b = b[:len(b)-SizeTag(num)]
+	return b, n
+}
+
+// SizeGroup returns the encoded size of a group, given only the length.
+func SizeGroup(num Number, n int) int {
+	return n + SizeTag(num)
+}
+
+// DecodeTag decodes the field Number and wire Type from its unified form.
+// The Number is -1 if the decoded field number overflows int32.
+// Other than overflow, this does not check for field number validity.
+func DecodeTag(x uint64) (Number, Type) {
+	// NOTE: MessageSet allows for larger field numbers than normal.
+	if x>>3 > uint64(math.MaxInt32) {
+		return -1, 0
+	}
+	return Number(x >> 3), Type(x & 7)
+}
+
+// EncodeTag encodes the field Number and wire Type into its unified form.
+func EncodeTag(num Number, typ Type) uint64 {
+	return uint64(num)<<3 | uint64(typ&7)
+}
+
+// DecodeZigZag decodes a zig-zag-encoded uint64 as an int64.
+//	Input:  {…,  5,  3,  1,  0,  2,  4,  6, …}
+//	Output: {…, -3, -2, -1,  0, +1, +2, +3, …}
+func DecodeZigZag(x uint64) int64 {
+	return int64(x>>1) ^ int64(x)<<63>>63
+}
+
+// EncodeZigZag encodes an int64 as a zig-zag-encoded uint64.
+//	Input:  {…, -3, -2, -1,  0, +1, +2, +3, …}
+//	Output: {…,  5,  3,  1,  0,  2,  4,  6, …}
+func EncodeZigZag(x int64) uint64 {
+	return uint64(x<<1) ^ uint64(x>>63)
+}
+
+// DecodeBool decodes a uint64 as a bool.
+//	Input:  {    0,    1,    2, …}
+//	Output: {false, true, true, …}
+func DecodeBool(x uint64) bool {
+	return x != 0
+}
+
+// EncodeBool encodes a bool as a uint64.
+//	Input:  {false, true}
+//	Output: {    0,    1}
+func EncodeBool(x bool) uint64 {
+	if x {
+		return 1
+	}
+	return 0
+}