diff --git a/vendor/google.golang.org/protobuf/internal/descfmt/stringer.go b/vendor/google.golang.org/protobuf/internal/descfmt/stringer.go
new file mode 100644
index 0000000..360c633
--- /dev/null
+++ b/vendor/google.golang.org/protobuf/internal/descfmt/stringer.go
@@ -0,0 +1,318 @@
+// 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 descfmt provides functionality to format descriptors.
+package descfmt
+
+import (
+	"fmt"
+	"io"
+	"reflect"
+	"strconv"
+	"strings"
+
+	"google.golang.org/protobuf/internal/detrand"
+	"google.golang.org/protobuf/internal/pragma"
+	pref "google.golang.org/protobuf/reflect/protoreflect"
+)
+
+type list interface {
+	Len() int
+	pragma.DoNotImplement
+}
+
+func FormatList(s fmt.State, r rune, vs list) {
+	io.WriteString(s, formatListOpt(vs, true, r == 'v' && (s.Flag('+') || s.Flag('#'))))
+}
+func formatListOpt(vs list, isRoot, allowMulti bool) string {
+	start, end := "[", "]"
+	if isRoot {
+		var name string
+		switch vs.(type) {
+		case pref.Names:
+			name = "Names"
+		case pref.FieldNumbers:
+			name = "FieldNumbers"
+		case pref.FieldRanges:
+			name = "FieldRanges"
+		case pref.EnumRanges:
+			name = "EnumRanges"
+		case pref.FileImports:
+			name = "FileImports"
+		case pref.Descriptor:
+			name = reflect.ValueOf(vs).MethodByName("Get").Type().Out(0).Name() + "s"
+		default:
+			name = reflect.ValueOf(vs).Elem().Type().Name()
+		}
+		start, end = name+"{", "}"
+	}
+
+	var ss []string
+	switch vs := vs.(type) {
+	case pref.Names:
+		for i := 0; i < vs.Len(); i++ {
+			ss = append(ss, fmt.Sprint(vs.Get(i)))
+		}
+		return start + joinStrings(ss, false) + end
+	case pref.FieldNumbers:
+		for i := 0; i < vs.Len(); i++ {
+			ss = append(ss, fmt.Sprint(vs.Get(i)))
+		}
+		return start + joinStrings(ss, false) + end
+	case pref.FieldRanges:
+		for i := 0; i < vs.Len(); i++ {
+			r := vs.Get(i)
+			if r[0]+1 == r[1] {
+				ss = append(ss, fmt.Sprintf("%d", r[0]))
+			} else {
+				ss = append(ss, fmt.Sprintf("%d:%d", r[0], r[1])) // enum ranges are end exclusive
+			}
+		}
+		return start + joinStrings(ss, false) + end
+	case pref.EnumRanges:
+		for i := 0; i < vs.Len(); i++ {
+			r := vs.Get(i)
+			if r[0] == r[1] {
+				ss = append(ss, fmt.Sprintf("%d", r[0]))
+			} else {
+				ss = append(ss, fmt.Sprintf("%d:%d", r[0], int64(r[1])+1)) // enum ranges are end inclusive
+			}
+		}
+		return start + joinStrings(ss, false) + end
+	case pref.FileImports:
+		for i := 0; i < vs.Len(); i++ {
+			var rs records
+			rs.Append(reflect.ValueOf(vs.Get(i)), "Path", "Package", "IsPublic", "IsWeak")
+			ss = append(ss, "{"+rs.Join()+"}")
+		}
+		return start + joinStrings(ss, allowMulti) + end
+	default:
+		_, isEnumValue := vs.(pref.EnumValueDescriptors)
+		for i := 0; i < vs.Len(); i++ {
+			m := reflect.ValueOf(vs).MethodByName("Get")
+			v := m.Call([]reflect.Value{reflect.ValueOf(i)})[0].Interface()
+			ss = append(ss, formatDescOpt(v.(pref.Descriptor), false, allowMulti && !isEnumValue))
+		}
+		return start + joinStrings(ss, allowMulti && isEnumValue) + end
+	}
+}
+
+// descriptorAccessors is a list of accessors to print for each descriptor.
+//
+// Do not print all accessors since some contain redundant information,
+// while others are pointers that we do not want to follow since the descriptor
+// is actually a cyclic graph.
+//
+// Using a list allows us to print the accessors in a sensible order.
+var descriptorAccessors = map[reflect.Type][]string{
+	reflect.TypeOf((*pref.FileDescriptor)(nil)).Elem():      {"Path", "Package", "Imports", "Messages", "Enums", "Extensions", "Services"},
+	reflect.TypeOf((*pref.MessageDescriptor)(nil)).Elem():   {"IsMapEntry", "Fields", "Oneofs", "ReservedNames", "ReservedRanges", "RequiredNumbers", "ExtensionRanges", "Messages", "Enums", "Extensions"},
+	reflect.TypeOf((*pref.FieldDescriptor)(nil)).Elem():     {"Number", "Cardinality", "Kind", "HasJSONName", "JSONName", "HasPresence", "IsExtension", "IsPacked", "IsWeak", "IsList", "IsMap", "MapKey", "MapValue", "HasDefault", "Default", "ContainingOneof", "ContainingMessage", "Message", "Enum"},
+	reflect.TypeOf((*pref.OneofDescriptor)(nil)).Elem():     {"Fields"}, // not directly used; must keep in sync with formatDescOpt
+	reflect.TypeOf((*pref.EnumDescriptor)(nil)).Elem():      {"Values", "ReservedNames", "ReservedRanges"},
+	reflect.TypeOf((*pref.EnumValueDescriptor)(nil)).Elem(): {"Number"},
+	reflect.TypeOf((*pref.ServiceDescriptor)(nil)).Elem():   {"Methods"},
+	reflect.TypeOf((*pref.MethodDescriptor)(nil)).Elem():    {"Input", "Output", "IsStreamingClient", "IsStreamingServer"},
+}
+
+func FormatDesc(s fmt.State, r rune, t pref.Descriptor) {
+	io.WriteString(s, formatDescOpt(t, true, r == 'v' && (s.Flag('+') || s.Flag('#'))))
+}
+func formatDescOpt(t pref.Descriptor, isRoot, allowMulti bool) string {
+	rv := reflect.ValueOf(t)
+	rt := rv.MethodByName("ProtoType").Type().In(0)
+
+	start, end := "{", "}"
+	if isRoot {
+		start = rt.Name() + "{"
+	}
+
+	_, isFile := t.(pref.FileDescriptor)
+	rs := records{allowMulti: allowMulti}
+	if t.IsPlaceholder() {
+		if isFile {
+			rs.Append(rv, "Path", "Package", "IsPlaceholder")
+		} else {
+			rs.Append(rv, "FullName", "IsPlaceholder")
+		}
+	} else {
+		switch {
+		case isFile:
+			rs.Append(rv, "Syntax")
+		case isRoot:
+			rs.Append(rv, "Syntax", "FullName")
+		default:
+			rs.Append(rv, "Name")
+		}
+		switch t := t.(type) {
+		case pref.FieldDescriptor:
+			for _, s := range descriptorAccessors[rt] {
+				switch s {
+				case "MapKey":
+					if k := t.MapKey(); k != nil {
+						rs.recs = append(rs.recs, [2]string{"MapKey", k.Kind().String()})
+					}
+				case "MapValue":
+					if v := t.MapValue(); v != nil {
+						switch v.Kind() {
+						case pref.EnumKind:
+							rs.recs = append(rs.recs, [2]string{"MapValue", string(v.Enum().FullName())})
+						case pref.MessageKind, pref.GroupKind:
+							rs.recs = append(rs.recs, [2]string{"MapValue", string(v.Message().FullName())})
+						default:
+							rs.recs = append(rs.recs, [2]string{"MapValue", v.Kind().String()})
+						}
+					}
+				case "ContainingOneof":
+					if od := t.ContainingOneof(); od != nil {
+						rs.recs = append(rs.recs, [2]string{"Oneof", string(od.Name())})
+					}
+				case "ContainingMessage":
+					if t.IsExtension() {
+						rs.recs = append(rs.recs, [2]string{"Extendee", string(t.ContainingMessage().FullName())})
+					}
+				case "Message":
+					if !t.IsMap() {
+						rs.Append(rv, s)
+					}
+				default:
+					rs.Append(rv, s)
+				}
+			}
+		case pref.OneofDescriptor:
+			var ss []string
+			fs := t.Fields()
+			for i := 0; i < fs.Len(); i++ {
+				ss = append(ss, string(fs.Get(i).Name()))
+			}
+			if len(ss) > 0 {
+				rs.recs = append(rs.recs, [2]string{"Fields", "[" + joinStrings(ss, false) + "]"})
+			}
+		default:
+			rs.Append(rv, descriptorAccessors[rt]...)
+		}
+		if rv.MethodByName("GoType").IsValid() {
+			rs.Append(rv, "GoType")
+		}
+	}
+	return start + rs.Join() + end
+}
+
+type records struct {
+	recs       [][2]string
+	allowMulti bool
+}
+
+func (rs *records) Append(v reflect.Value, accessors ...string) {
+	for _, a := range accessors {
+		var rv reflect.Value
+		if m := v.MethodByName(a); m.IsValid() {
+			rv = m.Call(nil)[0]
+		}
+		if v.Kind() == reflect.Struct && !rv.IsValid() {
+			rv = v.FieldByName(a)
+		}
+		if !rv.IsValid() {
+			panic(fmt.Sprintf("unknown accessor: %v.%s", v.Type(), a))
+		}
+		if _, ok := rv.Interface().(pref.Value); ok {
+			rv = rv.MethodByName("Interface").Call(nil)[0]
+			if !rv.IsNil() {
+				rv = rv.Elem()
+			}
+		}
+
+		// Ignore zero values.
+		var isZero bool
+		switch rv.Kind() {
+		case reflect.Interface, reflect.Slice:
+			isZero = rv.IsNil()
+		case reflect.Bool:
+			isZero = rv.Bool() == false
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+			isZero = rv.Int() == 0
+		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+			isZero = rv.Uint() == 0
+		case reflect.String:
+			isZero = rv.String() == ""
+		}
+		if n, ok := rv.Interface().(list); ok {
+			isZero = n.Len() == 0
+		}
+		if isZero {
+			continue
+		}
+
+		// Format the value.
+		var s string
+		v := rv.Interface()
+		switch v := v.(type) {
+		case list:
+			s = formatListOpt(v, false, rs.allowMulti)
+		case pref.FieldDescriptor, pref.OneofDescriptor, pref.EnumValueDescriptor, pref.MethodDescriptor:
+			s = string(v.(pref.Descriptor).Name())
+		case pref.Descriptor:
+			s = string(v.FullName())
+		case string:
+			s = strconv.Quote(v)
+		case []byte:
+			s = fmt.Sprintf("%q", v)
+		default:
+			s = fmt.Sprint(v)
+		}
+		rs.recs = append(rs.recs, [2]string{a, s})
+	}
+}
+
+func (rs *records) Join() string {
+	var ss []string
+
+	// In single line mode, simply join all records with commas.
+	if !rs.allowMulti {
+		for _, r := range rs.recs {
+			ss = append(ss, r[0]+formatColon(0)+r[1])
+		}
+		return joinStrings(ss, false)
+	}
+
+	// In allowMulti line mode, align single line records for more readable output.
+	var maxLen int
+	flush := func(i int) {
+		for _, r := range rs.recs[len(ss):i] {
+			ss = append(ss, r[0]+formatColon(maxLen-len(r[0]))+r[1])
+		}
+		maxLen = 0
+	}
+	for i, r := range rs.recs {
+		if isMulti := strings.Contains(r[1], "\n"); isMulti {
+			flush(i)
+			ss = append(ss, r[0]+formatColon(0)+strings.Join(strings.Split(r[1], "\n"), "\n\t"))
+		} else if maxLen < len(r[0]) {
+			maxLen = len(r[0])
+		}
+	}
+	flush(len(rs.recs))
+	return joinStrings(ss, true)
+}
+
+func formatColon(padding int) string {
+	// Deliberately introduce instability into the debug output to
+	// discourage users from performing string comparisons.
+	// This provides us flexibility to change the output in the future.
+	if detrand.Bool() {
+		return ":" + strings.Repeat(" ", 1+padding) // use non-breaking spaces (U+00a0)
+	} else {
+		return ":" + strings.Repeat(" ", 1+padding) // use regular spaces (U+0020)
+	}
+}
+
+func joinStrings(ss []string, isMulti bool) string {
+	if len(ss) == 0 {
+		return ""
+	}
+	if isMulti {
+		return "\n\t" + strings.Join(ss, "\n\t") + "\n"
+	}
+	return strings.Join(ss, ", ")
+}