diff --git a/vendor/github.com/jhump/protoreflect/dynamic/json.go b/vendor/github.com/jhump/protoreflect/dynamic/json.go
new file mode 100644
index 0000000..02c8298
--- /dev/null
+++ b/vendor/github.com/jhump/protoreflect/dynamic/json.go
@@ -0,0 +1,1256 @@
+package dynamic
+
+// JSON marshalling and unmarshalling for dynamic messages
+
+import (
+	"bytes"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"math"
+	"reflect"
+	"sort"
+	"strconv"
+	"strings"
+
+	"github.com/golang/protobuf/jsonpb"
+	"github.com/golang/protobuf/proto"
+	"github.com/golang/protobuf/protoc-gen-go/descriptor"
+	// link in the well-known-types that have a special JSON format
+	_ "github.com/golang/protobuf/ptypes/any"
+	_ "github.com/golang/protobuf/ptypes/duration"
+	_ "github.com/golang/protobuf/ptypes/empty"
+	_ "github.com/golang/protobuf/ptypes/struct"
+	_ "github.com/golang/protobuf/ptypes/timestamp"
+	_ "github.com/golang/protobuf/ptypes/wrappers"
+
+	"github.com/jhump/protoreflect/desc"
+)
+
+var wellKnownTypeNames = map[string]struct{}{
+	"google.protobuf.Any":       {},
+	"google.protobuf.Empty":     {},
+	"google.protobuf.Duration":  {},
+	"google.protobuf.Timestamp": {},
+	// struct.proto
+	"google.protobuf.Struct":    {},
+	"google.protobuf.Value":     {},
+	"google.protobuf.ListValue": {},
+	// wrappers.proto
+	"google.protobuf.DoubleValue": {},
+	"google.protobuf.FloatValue":  {},
+	"google.protobuf.Int64Value":  {},
+	"google.protobuf.UInt64Value": {},
+	"google.protobuf.Int32Value":  {},
+	"google.protobuf.UInt32Value": {},
+	"google.protobuf.BoolValue":   {},
+	"google.protobuf.StringValue": {},
+	"google.protobuf.BytesValue":  {},
+}
+
+// MarshalJSON serializes this message to bytes in JSON format, returning an
+// error if the operation fails. The resulting bytes will be a valid UTF8
+// string.
+//
+// This method uses a compact form: no newlines, and spaces between fields and
+// between field identifiers and values are elided.
+//
+// This method is convenient shorthand for invoking MarshalJSONPB with a default
+// (zero value) marshaler:
+//
+//    m.MarshalJSONPB(&jsonpb.Marshaler{})
+//
+// So enums are serialized using enum value name strings, and values that are
+// not present (including those with default/zero value for messages defined in
+// "proto3" syntax) are omitted.
+func (m *Message) MarshalJSON() ([]byte, error) {
+	return m.MarshalJSONPB(&jsonpb.Marshaler{})
+}
+
+// MarshalJSONIndent serializes this message to bytes in JSON format, returning
+// an error if the operation fails. The resulting bytes will be a valid UTF8
+// string.
+//
+// This method uses a "pretty-printed" form, with each field on its own line and
+// spaces between field identifiers and values. Indentation of two spaces is
+// used.
+//
+// This method is convenient shorthand for invoking MarshalJSONPB with a default
+// (zero value) marshaler:
+//
+//    m.MarshalJSONPB(&jsonpb.Marshaler{Indent: "  "})
+//
+// So enums are serialized using enum value name strings, and values that are
+// not present (including those with default/zero value for messages defined in
+// "proto3" syntax) are omitted.
+func (m *Message) MarshalJSONIndent() ([]byte, error) {
+	return m.MarshalJSONPB(&jsonpb.Marshaler{Indent: "  "})
+}
+
+// MarshalJSONPB serializes this message to bytes in JSON format, returning an
+// error if the operation fails. The resulting bytes will be a valid UTF8
+// string. The given marshaler is used to convey options used during marshaling.
+//
+// If this message contains nested messages that are generated message types (as
+// opposed to dynamic messages), the given marshaler is used to marshal it.
+//
+// When marshaling any nested messages, any jsonpb.AnyResolver configured in the
+// given marshaler is augmented with knowledge of message types known to this
+// message's descriptor (and its enclosing file and set of transitive
+// dependencies).
+func (m *Message) MarshalJSONPB(opts *jsonpb.Marshaler) ([]byte, error) {
+	var b indentBuffer
+	b.indent = opts.Indent
+	if len(opts.Indent) == 0 {
+		b.indentCount = -1
+	}
+	b.comma = true
+	if err := m.marshalJSON(&b, opts); err != nil {
+		return nil, err
+	}
+	return b.Bytes(), nil
+}
+
+func (m *Message) marshalJSON(b *indentBuffer, opts *jsonpb.Marshaler) error {
+	if m == nil {
+		_, err := b.WriteString("null")
+		return err
+	}
+	if r, changed := wrapResolver(opts.AnyResolver, m.mf, m.md.GetFile()); changed {
+		newOpts := *opts
+		newOpts.AnyResolver = r
+		opts = &newOpts
+	}
+
+	if ok, err := marshalWellKnownType(m, b, opts); ok {
+		return err
+	}
+
+	err := b.WriteByte('{')
+	if err != nil {
+		return err
+	}
+	err = b.start()
+	if err != nil {
+		return err
+	}
+
+	var tags []int
+	if opts.EmitDefaults {
+		tags = m.allKnownFieldTags()
+	} else {
+		tags = m.knownFieldTags()
+	}
+
+	first := true
+
+	for _, tag := range tags {
+		itag := int32(tag)
+		fd := m.FindFieldDescriptor(itag)
+
+		v, ok := m.values[itag]
+		if !ok {
+			if fd.GetOneOf() != nil {
+				// don't print defaults for fields in a oneof
+				continue
+			}
+			v = fd.GetDefaultValue()
+		}
+
+		err := b.maybeNext(&first)
+		if err != nil {
+			return err
+		}
+		err = marshalKnownFieldJSON(b, fd, v, opts)
+		if err != nil {
+			return err
+		}
+	}
+
+	err = b.end()
+	if err != nil {
+		return err
+	}
+	err = b.WriteByte('}')
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func marshalWellKnownType(m *Message, b *indentBuffer, opts *jsonpb.Marshaler) (bool, error) {
+	fqn := m.md.GetFullyQualifiedName()
+	if _, ok := wellKnownTypeNames[fqn]; !ok {
+		return false, nil
+	}
+
+	msgType := proto.MessageType(fqn)
+	if msgType == nil {
+		// wtf?
+		panic(fmt.Sprintf("could not find registered message type for %q", fqn))
+	}
+
+	// convert dynamic message to well-known type and let jsonpb marshal it
+	msg := reflect.New(msgType.Elem()).Interface().(proto.Message)
+	if err := m.MergeInto(msg); err != nil {
+		return true, err
+	}
+	return true, opts.Marshal(b, msg)
+}
+
+func marshalKnownFieldJSON(b *indentBuffer, fd *desc.FieldDescriptor, v interface{}, opts *jsonpb.Marshaler) error {
+	var jsonName string
+	if opts.OrigName {
+		jsonName = fd.GetName()
+	} else {
+		jsonName = fd.AsFieldDescriptorProto().GetJsonName()
+		if jsonName == "" {
+			jsonName = fd.GetName()
+		}
+	}
+	if fd.IsExtension() {
+		var scope string
+		switch parent := fd.GetParent().(type) {
+		case *desc.FileDescriptor:
+			scope = parent.GetPackage()
+		default:
+			scope = parent.GetFullyQualifiedName()
+		}
+		if scope == "" {
+			jsonName = fmt.Sprintf("[%s]", jsonName)
+		} else {
+			jsonName = fmt.Sprintf("[%s.%s]", scope, jsonName)
+		}
+	}
+	err := writeJsonString(b, jsonName)
+	if err != nil {
+		return err
+	}
+	err = b.sep()
+	if err != nil {
+		return err
+	}
+
+	if isNil(v) {
+		_, err := b.WriteString("null")
+		return err
+	}
+
+	if fd.IsMap() {
+		err = b.WriteByte('{')
+		if err != nil {
+			return err
+		}
+		err = b.start()
+		if err != nil {
+			return err
+		}
+
+		md := fd.GetMessageType()
+		vfd := md.FindFieldByNumber(2)
+
+		mp := v.(map[interface{}]interface{})
+		keys := make([]interface{}, 0, len(mp))
+		for k := range mp {
+			keys = append(keys, k)
+		}
+		sort.Sort(sortable(keys))
+		first := true
+		for _, mk := range keys {
+			mv := mp[mk]
+			err := b.maybeNext(&first)
+			if err != nil {
+				return err
+			}
+
+			err = marshalKnownFieldMapEntryJSON(b, mk, vfd, mv, opts)
+			if err != nil {
+				return err
+			}
+		}
+
+		err = b.end()
+		if err != nil {
+			return err
+		}
+		return b.WriteByte('}')
+
+	} else if fd.IsRepeated() {
+		err = b.WriteByte('[')
+		if err != nil {
+			return err
+		}
+		err = b.start()
+		if err != nil {
+			return err
+		}
+
+		sl := v.([]interface{})
+		first := true
+		for _, slv := range sl {
+			err := b.maybeNext(&first)
+			if err != nil {
+				return err
+			}
+			err = marshalKnownFieldValueJSON(b, fd, slv, opts)
+			if err != nil {
+				return err
+			}
+		}
+
+		err = b.end()
+		if err != nil {
+			return err
+		}
+		return b.WriteByte(']')
+
+	} else {
+		return marshalKnownFieldValueJSON(b, fd, v, opts)
+	}
+}
+
+// sortable is used to sort map keys. Values will be integers (int32, int64, uint32, and uint64),
+// bools, or strings.
+type sortable []interface{}
+
+func (s sortable) Len() int {
+	return len(s)
+}
+
+func (s sortable) Less(i, j int) bool {
+	vi := s[i]
+	vj := s[j]
+	switch reflect.TypeOf(vi).Kind() {
+	case reflect.Int32:
+		return vi.(int32) < vj.(int32)
+	case reflect.Int64:
+		return vi.(int64) < vj.(int64)
+	case reflect.Uint32:
+		return vi.(uint32) < vj.(uint32)
+	case reflect.Uint64:
+		return vi.(uint64) < vj.(uint64)
+	case reflect.String:
+		return vi.(string) < vj.(string)
+	case reflect.Bool:
+		return !vi.(bool) && vj.(bool)
+	default:
+		panic(fmt.Sprintf("cannot compare keys of type %v", reflect.TypeOf(vi)))
+	}
+}
+
+func (s sortable) Swap(i, j int) {
+	s[i], s[j] = s[j], s[i]
+}
+
+func isNil(v interface{}) bool {
+	if v == nil {
+		return true
+	}
+	rv := reflect.ValueOf(v)
+	return rv.Kind() == reflect.Ptr && rv.IsNil()
+}
+
+func marshalKnownFieldMapEntryJSON(b *indentBuffer, mk interface{}, vfd *desc.FieldDescriptor, mv interface{}, opts *jsonpb.Marshaler) error {
+	rk := reflect.ValueOf(mk)
+	var strkey string
+	switch rk.Kind() {
+	case reflect.Bool:
+		strkey = strconv.FormatBool(rk.Bool())
+	case reflect.Int32, reflect.Int64:
+		strkey = strconv.FormatInt(rk.Int(), 10)
+	case reflect.Uint32, reflect.Uint64:
+		strkey = strconv.FormatUint(rk.Uint(), 10)
+	case reflect.String:
+		strkey = rk.String()
+	default:
+		return fmt.Errorf("invalid map key value: %v (%v)", mk, rk.Type())
+	}
+	err := writeJsonString(b, strkey)
+	if err != nil {
+		return err
+	}
+	err = b.sep()
+	if err != nil {
+		return err
+	}
+	return marshalKnownFieldValueJSON(b, vfd, mv, opts)
+}
+
+func marshalKnownFieldValueJSON(b *indentBuffer, fd *desc.FieldDescriptor, v interface{}, opts *jsonpb.Marshaler) error {
+	rv := reflect.ValueOf(v)
+	switch rv.Kind() {
+	case reflect.Int64:
+		return writeJsonString(b, strconv.FormatInt(rv.Int(), 10))
+	case reflect.Int32:
+		ed := fd.GetEnumType()
+		if !opts.EnumsAsInts && ed != nil {
+			n := int32(rv.Int())
+			vd := ed.FindValueByNumber(n)
+			if vd == nil {
+				_, err := b.WriteString(strconv.FormatInt(rv.Int(), 10))
+				return err
+			} else {
+				return writeJsonString(b, vd.GetName())
+			}
+		} else {
+			_, err := b.WriteString(strconv.FormatInt(rv.Int(), 10))
+			return err
+		}
+	case reflect.Uint64:
+		return writeJsonString(b, strconv.FormatUint(rv.Uint(), 10))
+	case reflect.Uint32:
+		_, err := b.WriteString(strconv.FormatUint(rv.Uint(), 10))
+		return err
+	case reflect.Float32, reflect.Float64:
+		f := rv.Float()
+		var str string
+		if math.IsNaN(f) {
+			str = `"NaN"`
+		} else if math.IsInf(f, 1) {
+			str = `"Infinity"`
+		} else if math.IsInf(f, -1) {
+			str = `"-Infinity"`
+		} else {
+			var bits int
+			if rv.Kind() == reflect.Float32 {
+				bits = 32
+			} else {
+				bits = 64
+			}
+			str = strconv.FormatFloat(rv.Float(), 'g', -1, bits)
+		}
+		_, err := b.WriteString(str)
+		return err
+	case reflect.Bool:
+		_, err := b.WriteString(strconv.FormatBool(rv.Bool()))
+		return err
+	case reflect.Slice:
+		bstr := base64.StdEncoding.EncodeToString(rv.Bytes())
+		return writeJsonString(b, bstr)
+	case reflect.String:
+		return writeJsonString(b, rv.String())
+	default:
+		// must be a message
+		if isNil(v) {
+			_, err := b.WriteString("null")
+			return err
+		}
+
+		if dm, ok := v.(*Message); ok {
+			return dm.marshalJSON(b, opts)
+		}
+
+		var err error
+		if b.indentCount <= 0 || len(b.indent) == 0 {
+			err = opts.Marshal(b, v.(proto.Message))
+		} else {
+			str, err := opts.MarshalToString(v.(proto.Message))
+			if err != nil {
+				return err
+			}
+			indent := strings.Repeat(b.indent, b.indentCount)
+			pos := 0
+			// add indention prefix to each line
+			for pos < len(str) {
+				start := pos
+				nextPos := strings.Index(str[pos:], "\n")
+				if nextPos == -1 {
+					nextPos = len(str)
+				} else {
+					nextPos = pos + nextPos + 1 // include newline
+				}
+				line := str[start:nextPos]
+				if pos > 0 {
+					_, err = b.WriteString(indent)
+					if err != nil {
+						return err
+					}
+				}
+				_, err = b.WriteString(line)
+				if err != nil {
+					return err
+				}
+				pos = nextPos
+			}
+		}
+		return err
+	}
+}
+
+func writeJsonString(b *indentBuffer, s string) error {
+	if sbytes, err := json.Marshal(s); err != nil {
+		return err
+	} else {
+		_, err := b.Write(sbytes)
+		return err
+	}
+}
+
+// UnmarshalJSON de-serializes the message that is present, in JSON format, in
+// the given bytes into this message. It first resets the current message. It
+// returns an error if the given bytes do not contain a valid encoding of this
+// message type in JSON format.
+//
+// This method is shorthand for invoking UnmarshalJSONPB with a default (zero
+// value) unmarshaler:
+//
+//    m.UnmarshalMergeJSONPB(&jsonpb.Unmarshaler{}, js)
+//
+// So unknown fields will result in an error, and no provided jsonpb.AnyResolver
+// will be used when parsing google.protobuf.Any messages.
+func (m *Message) UnmarshalJSON(js []byte) error {
+	return m.UnmarshalJSONPB(&jsonpb.Unmarshaler{}, js)
+}
+
+// UnmarshalMergeJSON de-serializes the message that is present, in JSON format,
+// in the given bytes into this message. Unlike UnmarshalJSON, it does not first
+// reset the message, instead merging the data in the given bytes into the
+// existing data in this message.
+func (m *Message) UnmarshalMergeJSON(js []byte) error {
+	return m.UnmarshalMergeJSONPB(&jsonpb.Unmarshaler{}, js)
+}
+
+// UnmarshalJSONPB de-serializes the message that is present, in JSON format, in
+// the given bytes into this message. The given unmarshaler conveys options used
+// when parsing the JSON. This function first resets the current message. It
+// returns an error if the given bytes do not contain a valid encoding of this
+// message type in JSON format.
+//
+// The decoding is lenient:
+//  1. The JSON can refer to fields either by their JSON name or by their
+//     declared name.
+//  2. The JSON can use either numeric values or string names for enum values.
+//
+// When instantiating nested messages, if this message's associated factory
+// returns a generated message type (as opposed to a dynamic message), the given
+// unmarshaler is used to unmarshal it.
+//
+// When unmarshaling any nested messages, any jsonpb.AnyResolver configured in
+// the given unmarshaler is augmented with knowledge of message types known to
+// this message's descriptor (and its enclosing file and set of transitive
+// dependencies).
+func (m *Message) UnmarshalJSONPB(opts *jsonpb.Unmarshaler, js []byte) error {
+	m.Reset()
+	if err := m.UnmarshalMergeJSONPB(opts, js); err != nil {
+		return err
+	}
+	return m.Validate()
+}
+
+// UnmarshalMergeJSONPB de-serializes the message that is present, in JSON
+// format, in the given bytes into this message. The given unmarshaler conveys
+// options used when parsing the JSON. Unlike UnmarshalJSONPB, it does not first
+// reset the message, instead merging the data in the given bytes into the
+// existing data in this message.
+func (m *Message) UnmarshalMergeJSONPB(opts *jsonpb.Unmarshaler, js []byte) error {
+	r := newJsReader(js)
+	err := m.unmarshalJson(r, opts)
+	if err != nil {
+		return err
+	}
+	if t, err := r.poll(); err != io.EOF {
+		b, _ := ioutil.ReadAll(r.unread())
+		s := fmt.Sprintf("%v%s", t, string(b))
+		return fmt.Errorf("superfluous data found after JSON object: %q", s)
+	}
+	return nil
+}
+
+func unmarshalWellKnownType(m *Message, r *jsReader, opts *jsonpb.Unmarshaler) (bool, error) {
+	fqn := m.md.GetFullyQualifiedName()
+	if _, ok := wellKnownTypeNames[fqn]; !ok {
+		return false, nil
+	}
+
+	msgType := proto.MessageType(fqn)
+	if msgType == nil {
+		// wtf?
+		panic(fmt.Sprintf("could not find registered message type for %q", fqn))
+	}
+
+	// extract json value from r
+	var js json.RawMessage
+	if err := json.NewDecoder(r.unread()).Decode(&js); err != nil {
+		return true, err
+	}
+	if err := r.skip(); err != nil {
+		return true, err
+	}
+
+	// unmarshal into well-known type and then convert to dynamic message
+	msg := reflect.New(msgType.Elem()).Interface().(proto.Message)
+	if err := opts.Unmarshal(bytes.NewReader(js), msg); err != nil {
+		return true, err
+	}
+	return true, m.MergeFrom(msg)
+}
+
+func (m *Message) unmarshalJson(r *jsReader, opts *jsonpb.Unmarshaler) error {
+	if r, changed := wrapResolver(opts.AnyResolver, m.mf, m.md.GetFile()); changed {
+		newOpts := *opts
+		newOpts.AnyResolver = r
+		opts = &newOpts
+	}
+
+	if ok, err := unmarshalWellKnownType(m, r, opts); ok {
+		return err
+	}
+
+	t, err := r.peek()
+	if err != nil {
+		return err
+	}
+	if t == nil {
+		// if json is simply "null" we do nothing
+		r.poll()
+		return nil
+	}
+
+	if err := r.beginObject(); err != nil {
+		return err
+	}
+
+	for r.hasNext() {
+		f, err := r.nextObjectKey()
+		if err != nil {
+			return err
+		}
+		fd := m.FindFieldDescriptorByJSONName(f)
+		if fd == nil {
+			if opts.AllowUnknownFields {
+				r.skip()
+				continue
+			}
+			return fmt.Errorf("message type %s has no known field named %s", m.md.GetFullyQualifiedName(), f)
+		}
+		v, err := unmarshalJsField(fd, r, m.mf, opts)
+		if err != nil {
+			return err
+		}
+		if v != nil {
+			if err := mergeField(m, fd, v); err != nil {
+				return err
+			}
+		} else if fd.GetOneOf() != nil {
+			// preserve explicit null for oneof fields (this is a little odd but
+			// mimics the behavior of jsonpb with oneofs in generated message types)
+			if fd.GetMessageType() != nil {
+				typ := m.mf.GetKnownTypeRegistry().GetKnownType(fd.GetMessageType().GetFullyQualifiedName())
+				if typ != nil {
+					// typed nil
+					if typ.Kind() != reflect.Ptr {
+						typ = reflect.PtrTo(typ)
+					}
+					v = reflect.Zero(typ).Interface()
+				} else {
+					// can't use nil dynamic message, so we just use empty one instead
+					v = m.mf.NewDynamicMessage(fd.GetMessageType())
+				}
+				if err := m.setField(fd, v); err != nil {
+					return err
+				}
+			} else {
+				// not a message... explicit null makes no sense
+				return fmt.Errorf("message type %s cannot set field %s to null: it is not a message type", m.md.GetFullyQualifiedName(), f)
+			}
+		} else {
+			m.clearField(fd)
+		}
+	}
+
+	if err := r.endObject(); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func isWellKnownValue(fd *desc.FieldDescriptor) bool {
+	return !fd.IsRepeated() && fd.GetType() == descriptor.FieldDescriptorProto_TYPE_MESSAGE &&
+		fd.GetMessageType().GetFullyQualifiedName() == "google.protobuf.Value"
+}
+
+func isWellKnownListValue(fd *desc.FieldDescriptor) bool {
+	// we look for ListValue; but we also look for Value, which can be assigned a ListValue
+	return !fd.IsRepeated() && fd.GetType() == descriptor.FieldDescriptorProto_TYPE_MESSAGE &&
+		(fd.GetMessageType().GetFullyQualifiedName() == "google.protobuf.ListValue" ||
+			fd.GetMessageType().GetFullyQualifiedName() == "google.protobuf.Value")
+}
+
+func unmarshalJsField(fd *desc.FieldDescriptor, r *jsReader, mf *MessageFactory, opts *jsonpb.Unmarshaler) (interface{}, error) {
+	t, err := r.peek()
+	if err != nil {
+		return nil, err
+	}
+	if t == nil && !isWellKnownValue(fd) {
+		// if value is null, just return nil
+		// (unless field is google.protobuf.Value, in which case
+		// we fall through to parse it as an instance where its
+		// underlying value is set to a NullValue)
+		r.poll()
+		return nil, nil
+	}
+
+	if t == json.Delim('{') && fd.IsMap() {
+		entryType := fd.GetMessageType()
+		keyType := entryType.FindFieldByNumber(1)
+		valueType := entryType.FindFieldByNumber(2)
+		mp := map[interface{}]interface{}{}
+
+		// TODO: if there are just two map keys "key" and "value" and they have the right type of values,
+		// treat this JSON object as a single map entry message. (In keeping with support of map fields as
+		// if they were normal repeated field of entry messages as well as supporting a transition from
+		// optional to repeated...)
+
+		if err := r.beginObject(); err != nil {
+			return nil, err
+		}
+		for r.hasNext() {
+			kk, err := unmarshalJsFieldElement(keyType, r, mf, opts, false)
+			if err != nil {
+				return nil, err
+			}
+			vv, err := unmarshalJsFieldElement(valueType, r, mf, opts, true)
+			if err != nil {
+				return nil, err
+			}
+			mp[kk] = vv
+		}
+		if err := r.endObject(); err != nil {
+			return nil, err
+		}
+
+		return mp, nil
+	} else if t == json.Delim('[') && !isWellKnownListValue(fd) {
+		// We support parsing an array, even if field is not repeated, to mimic support in proto
+		// binary wire format that supports changing an optional field to repeated and vice versa.
+		// If the field is not repeated, we only keep the last value in the array.
+
+		if err := r.beginArray(); err != nil {
+			return nil, err
+		}
+		var sl []interface{}
+		var v interface{}
+		for r.hasNext() {
+			var err error
+			v, err = unmarshalJsFieldElement(fd, r, mf, opts, false)
+			if err != nil {
+				return nil, err
+			}
+			if fd.IsRepeated() && v != nil {
+				sl = append(sl, v)
+			}
+		}
+		if err := r.endArray(); err != nil {
+			return nil, err
+		}
+		if fd.IsMap() {
+			mp := map[interface{}]interface{}{}
+			for _, m := range sl {
+				msg := m.(*Message)
+				kk, err := msg.TryGetFieldByNumber(1)
+				if err != nil {
+					return nil, err
+				}
+				vv, err := msg.TryGetFieldByNumber(2)
+				if err != nil {
+					return nil, err
+				}
+				mp[kk] = vv
+			}
+			return mp, nil
+		} else if fd.IsRepeated() {
+			return sl, nil
+		} else {
+			return v, nil
+		}
+	} else {
+		// We support parsing a singular value, even if field is repeated, to mimic support in proto
+		// binary wire format that supports changing an optional field to repeated and vice versa.
+		// If the field is repeated, we store value as singleton slice of that one value.
+
+		v, err := unmarshalJsFieldElement(fd, r, mf, opts, false)
+		if err != nil {
+			return nil, err
+		}
+		if v == nil {
+			return nil, nil
+		}
+		if fd.IsRepeated() {
+			return []interface{}{v}, nil
+		} else {
+			return v, nil
+		}
+	}
+}
+
+func unmarshalJsFieldElement(fd *desc.FieldDescriptor, r *jsReader, mf *MessageFactory, opts *jsonpb.Unmarshaler, allowNilMessage bool) (interface{}, error) {
+	t, err := r.peek()
+	if err != nil {
+		return nil, err
+	}
+
+	switch fd.GetType() {
+	case descriptor.FieldDescriptorProto_TYPE_MESSAGE,
+		descriptor.FieldDescriptorProto_TYPE_GROUP:
+
+		if t == nil && allowNilMessage {
+			// if json is simply "null" return a nil pointer
+			r.poll()
+			return nilMessage(fd.GetMessageType()), nil
+		}
+
+		m := mf.NewMessage(fd.GetMessageType())
+		if dm, ok := m.(*Message); ok {
+			if err := dm.unmarshalJson(r, opts); err != nil {
+				return nil, err
+			}
+		} else {
+			var msg json.RawMessage
+			if err := json.NewDecoder(r.unread()).Decode(&msg); err != nil {
+				return nil, err
+			}
+			if err := r.skip(); err != nil {
+				return nil, err
+			}
+			if err := opts.Unmarshal(bytes.NewReader([]byte(msg)), m); err != nil {
+				return nil, err
+			}
+		}
+		return m, nil
+
+	case descriptor.FieldDescriptorProto_TYPE_ENUM:
+		if e, err := r.nextNumber(); err != nil {
+			return nil, err
+		} else {
+			// value could be string or number
+			if i, err := e.Int64(); err != nil {
+				// number cannot be parsed, so see if it's an enum value name
+				vd := fd.GetEnumType().FindValueByName(string(e))
+				if vd != nil {
+					return vd.GetNumber(), nil
+				} else {
+					return nil, fmt.Errorf("enum %q does not have value named %q", fd.GetEnumType().GetFullyQualifiedName(), e)
+				}
+			} else if i > math.MaxInt32 || i < math.MinInt32 {
+				return nil, NumericOverflowError
+			} else {
+				return int32(i), err
+			}
+		}
+
+	case descriptor.FieldDescriptorProto_TYPE_INT32,
+		descriptor.FieldDescriptorProto_TYPE_SINT32,
+		descriptor.FieldDescriptorProto_TYPE_SFIXED32:
+		if i, err := r.nextInt(); err != nil {
+			return nil, err
+		} else if i > math.MaxInt32 || i < math.MinInt32 {
+			return nil, NumericOverflowError
+		} else {
+			return int32(i), err
+		}
+
+	case descriptor.FieldDescriptorProto_TYPE_INT64,
+		descriptor.FieldDescriptorProto_TYPE_SINT64,
+		descriptor.FieldDescriptorProto_TYPE_SFIXED64:
+		return r.nextInt()
+
+	case descriptor.FieldDescriptorProto_TYPE_UINT32,
+		descriptor.FieldDescriptorProto_TYPE_FIXED32:
+		if i, err := r.nextUint(); err != nil {
+			return nil, err
+		} else if i > math.MaxUint32 {
+			return nil, NumericOverflowError
+		} else {
+			return uint32(i), err
+		}
+
+	case descriptor.FieldDescriptorProto_TYPE_UINT64,
+		descriptor.FieldDescriptorProto_TYPE_FIXED64:
+		return r.nextUint()
+
+	case descriptor.FieldDescriptorProto_TYPE_BOOL:
+		if str, ok := t.(string); ok {
+			if str == "true" {
+				r.poll() // consume token
+				return true, err
+			} else if str == "false" {
+				r.poll() // consume token
+				return false, err
+			}
+		}
+		return r.nextBool()
+
+	case descriptor.FieldDescriptorProto_TYPE_FLOAT:
+		if f, err := r.nextFloat(); err != nil {
+			return nil, err
+		} else {
+			return float32(f), nil
+		}
+
+	case descriptor.FieldDescriptorProto_TYPE_DOUBLE:
+		return r.nextFloat()
+
+	case descriptor.FieldDescriptorProto_TYPE_BYTES:
+		return r.nextBytes()
+
+	case descriptor.FieldDescriptorProto_TYPE_STRING:
+		return r.nextString()
+
+	default:
+		return nil, fmt.Errorf("unknown field type: %v", fd.GetType())
+	}
+}
+
+type jsReader struct {
+	reader  *bytes.Reader
+	dec     *json.Decoder
+	current json.Token
+	peeked  bool
+}
+
+func newJsReader(b []byte) *jsReader {
+	reader := bytes.NewReader(b)
+	dec := json.NewDecoder(reader)
+	dec.UseNumber()
+	return &jsReader{reader: reader, dec: dec}
+}
+
+func (r *jsReader) unread() io.Reader {
+	bufs := make([]io.Reader, 3)
+	var peeked []byte
+	if r.peeked {
+		if _, ok := r.current.(json.Delim); ok {
+			peeked = []byte(fmt.Sprintf("%v", r.current))
+		} else {
+			peeked, _ = json.Marshal(r.current)
+		}
+	}
+	readerCopy := *r.reader
+	decCopy := *r.dec
+
+	bufs[0] = bytes.NewReader(peeked)
+	bufs[1] = decCopy.Buffered()
+	bufs[2] = &readerCopy
+	return &concatReader{bufs: bufs}
+}
+
+func (r *jsReader) hasNext() bool {
+	return r.dec.More()
+}
+
+func (r *jsReader) peek() (json.Token, error) {
+	if r.peeked {
+		return r.current, nil
+	}
+	t, err := r.dec.Token()
+	if err != nil {
+		return nil, err
+	}
+	r.peeked = true
+	r.current = t
+	return t, nil
+}
+
+func (r *jsReader) poll() (json.Token, error) {
+	if r.peeked {
+		ret := r.current
+		r.current = nil
+		r.peeked = false
+		return ret, nil
+	}
+	return r.dec.Token()
+}
+
+func (r *jsReader) beginObject() error {
+	_, err := r.expect(func(t json.Token) bool { return t == json.Delim('{') }, nil, "start of JSON object: '{'")
+	return err
+}
+
+func (r *jsReader) endObject() error {
+	_, err := r.expect(func(t json.Token) bool { return t == json.Delim('}') }, nil, "end of JSON object: '}'")
+	return err
+}
+
+func (r *jsReader) beginArray() error {
+	_, err := r.expect(func(t json.Token) bool { return t == json.Delim('[') }, nil, "start of array: '['")
+	return err
+}
+
+func (r *jsReader) endArray() error {
+	_, err := r.expect(func(t json.Token) bool { return t == json.Delim(']') }, nil, "end of array: ']'")
+	return err
+}
+
+func (r *jsReader) nextObjectKey() (string, error) {
+	return r.nextString()
+}
+
+func (r *jsReader) nextString() (string, error) {
+	t, err := r.expect(func(t json.Token) bool { _, ok := t.(string); return ok }, "", "string")
+	if err != nil {
+		return "", err
+	}
+	return t.(string), nil
+}
+
+func (r *jsReader) nextBytes() ([]byte, error) {
+	str, err := r.nextString()
+	if err != nil {
+		return nil, err
+	}
+	return base64.StdEncoding.DecodeString(str)
+}
+
+func (r *jsReader) nextBool() (bool, error) {
+	t, err := r.expect(func(t json.Token) bool { _, ok := t.(bool); return ok }, false, "boolean")
+	if err != nil {
+		return false, err
+	}
+	return t.(bool), nil
+}
+
+func (r *jsReader) nextInt() (int64, error) {
+	n, err := r.nextNumber()
+	if err != nil {
+		return 0, err
+	}
+	return n.Int64()
+}
+
+func (r *jsReader) nextUint() (uint64, error) {
+	n, err := r.nextNumber()
+	if err != nil {
+		return 0, err
+	}
+	return strconv.ParseUint(string(n), 10, 64)
+}
+
+func (r *jsReader) nextFloat() (float64, error) {
+	n, err := r.nextNumber()
+	if err != nil {
+		return 0, err
+	}
+	return n.Float64()
+}
+
+func (r *jsReader) nextNumber() (json.Number, error) {
+	t, err := r.expect(func(t json.Token) bool { return reflect.TypeOf(t).Kind() == reflect.String }, "0", "number")
+	if err != nil {
+		return "", err
+	}
+	switch t := t.(type) {
+	case json.Number:
+		return t, nil
+	case string:
+		return json.Number(t), nil
+	}
+	return "", fmt.Errorf("expecting a number but got %v", t)
+}
+
+func (r *jsReader) skip() error {
+	t, err := r.poll()
+	if err != nil {
+		return err
+	}
+	if t == json.Delim('[') {
+		if err := r.skipArray(); err != nil {
+			return err
+		}
+	} else if t == json.Delim('{') {
+		if err := r.skipObject(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (r *jsReader) skipArray() error {
+	for r.hasNext() {
+		if err := r.skip(); err != nil {
+			return err
+		}
+	}
+	if err := r.endArray(); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (r *jsReader) skipObject() error {
+	for r.hasNext() {
+		// skip object key
+		if err := r.skip(); err != nil {
+			return err
+		}
+		// and value
+		if err := r.skip(); err != nil {
+			return err
+		}
+	}
+	if err := r.endObject(); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (r *jsReader) expect(predicate func(json.Token) bool, ifNil interface{}, expected string) (interface{}, error) {
+	t, err := r.poll()
+	if err != nil {
+		return nil, err
+	}
+	if t == nil && ifNil != nil {
+		return ifNil, nil
+	}
+	if !predicate(t) {
+		return t, fmt.Errorf("bad input: expecting %s ; instead got %v", expected, t)
+	}
+	return t, nil
+}
+
+type concatReader struct {
+	bufs []io.Reader
+	curr int
+}
+
+func (r *concatReader) Read(p []byte) (n int, err error) {
+	for {
+		if r.curr >= len(r.bufs) {
+			err = io.EOF
+			return
+		}
+		var c int
+		c, err = r.bufs[r.curr].Read(p)
+		n += c
+		if err != io.EOF {
+			return
+		}
+		r.curr++
+		p = p[c:]
+	}
+}
+
+// AnyResolver returns a jsonpb.AnyResolver that uses the given file descriptors
+// to resolve message names. It uses the given factory, which may be nil, to
+// instantiate messages. The messages that it returns when resolving a type name
+// may often be dynamic messages.
+func AnyResolver(mf *MessageFactory, files ...*desc.FileDescriptor) jsonpb.AnyResolver {
+	return &anyResolver{mf: mf, files: files}
+}
+
+type anyResolver struct {
+	mf      *MessageFactory
+	files   []*desc.FileDescriptor
+	ignored map[*desc.FileDescriptor]struct{}
+	other   jsonpb.AnyResolver
+}
+
+func wrapResolver(r jsonpb.AnyResolver, mf *MessageFactory, f *desc.FileDescriptor) (jsonpb.AnyResolver, bool) {
+	if r, ok := r.(*anyResolver); ok {
+		if _, ok := r.ignored[f]; ok {
+			// if the current resolver is ignoring this file, it's because another
+			// (upstream) resolver is already handling it, so nothing to do
+			return r, false
+		}
+		for _, file := range r.files {
+			if file == f {
+				// no need to wrap!
+				return r, false
+			}
+		}
+		// ignore files that will be checked by the resolver we're wrapping
+		// (we'll just delegate and let it search those files)
+		ignored := map[*desc.FileDescriptor]struct{}{}
+		for i := range r.ignored {
+			ignored[i] = struct{}{}
+		}
+		ignore(r.files, ignored)
+		return &anyResolver{mf: mf, files: []*desc.FileDescriptor{f}, ignored: ignored, other: r}, true
+	}
+	return &anyResolver{mf: mf, files: []*desc.FileDescriptor{f}, other: r}, true
+}
+
+func ignore(files []*desc.FileDescriptor, ignored map[*desc.FileDescriptor]struct{}) {
+	for _, f := range files {
+		if _, ok := ignored[f]; ok {
+			continue
+		}
+		ignored[f] = struct{}{}
+		ignore(f.GetDependencies(), ignored)
+	}
+}
+
+func (r *anyResolver) Resolve(typeUrl string) (proto.Message, error) {
+	mname := typeUrl
+	if slash := strings.LastIndex(mname, "/"); slash >= 0 {
+		mname = mname[slash+1:]
+	}
+
+	// see if the user-specified resolver is able to do the job
+	if r.other != nil {
+		msg, err := r.other.Resolve(typeUrl)
+		if err == nil {
+			return msg, nil
+		}
+	}
+
+	// try to find the message in our known set of files
+	checked := map[*desc.FileDescriptor]struct{}{}
+	for _, f := range r.files {
+		md := r.findMessage(f, mname, checked)
+		if md != nil {
+			return r.mf.NewMessage(md), nil
+		}
+	}
+	// failing that, see if the message factory knows about this type
+	var ktr *KnownTypeRegistry
+	if r.mf != nil {
+		ktr = r.mf.ktr
+	} else {
+		ktr = (*KnownTypeRegistry)(nil)
+	}
+	m := ktr.CreateIfKnown(mname)
+	if m != nil {
+		return m, nil
+	}
+
+	// no other resolver to fallback to? mimic default behavior
+	mt := proto.MessageType(mname)
+	if mt == nil {
+		return nil, fmt.Errorf("unknown message type %q", mname)
+	}
+	return reflect.New(mt.Elem()).Interface().(proto.Message), nil
+}
+
+func (r *anyResolver) findMessage(fd *desc.FileDescriptor, msgName string, checked map[*desc.FileDescriptor]struct{}) *desc.MessageDescriptor {
+	// if this is an ignored descriptor, skip
+	if _, ok := r.ignored[fd]; ok {
+		return nil
+	}
+
+	// bail if we've already checked this file
+	if _, ok := checked[fd]; ok {
+		return nil
+	}
+	checked[fd] = struct{}{}
+
+	// see if this file has the message
+	md := fd.FindMessage(msgName)
+	if md != nil {
+		return md
+	}
+
+	// if not, recursively search the file's imports
+	for _, dep := range fd.GetDependencies() {
+		md = r.findMessage(dep, msgName, checked)
+		if md != nil {
+			return md
+		}
+	}
+	return nil
+}
+
+var _ jsonpb.AnyResolver = (*anyResolver)(nil)