diff --git a/vendor/github.com/json-iterator/go/reflect_extension.go b/vendor/github.com/json-iterator/go/reflect_extension.go
new file mode 100644
index 0000000..05e8fbf
--- /dev/null
+++ b/vendor/github.com/json-iterator/go/reflect_extension.go
@@ -0,0 +1,483 @@
+package jsoniter
+
+import (
+	"fmt"
+	"github.com/modern-go/reflect2"
+	"reflect"
+	"sort"
+	"strings"
+	"unicode"
+	"unsafe"
+)
+
+var typeDecoders = map[string]ValDecoder{}
+var fieldDecoders = map[string]ValDecoder{}
+var typeEncoders = map[string]ValEncoder{}
+var fieldEncoders = map[string]ValEncoder{}
+var extensions = []Extension{}
+
+// StructDescriptor describe how should we encode/decode the struct
+type StructDescriptor struct {
+	Type   reflect2.Type
+	Fields []*Binding
+}
+
+// GetField get one field from the descriptor by its name.
+// Can not use map here to keep field orders.
+func (structDescriptor *StructDescriptor) GetField(fieldName string) *Binding {
+	for _, binding := range structDescriptor.Fields {
+		if binding.Field.Name() == fieldName {
+			return binding
+		}
+	}
+	return nil
+}
+
+// Binding describe how should we encode/decode the struct field
+type Binding struct {
+	levels    []int
+	Field     reflect2.StructField
+	FromNames []string
+	ToNames   []string
+	Encoder   ValEncoder
+	Decoder   ValDecoder
+}
+
+// Extension the one for all SPI. Customize encoding/decoding by specifying alternate encoder/decoder.
+// Can also rename fields by UpdateStructDescriptor.
+type Extension interface {
+	UpdateStructDescriptor(structDescriptor *StructDescriptor)
+	CreateMapKeyDecoder(typ reflect2.Type) ValDecoder
+	CreateMapKeyEncoder(typ reflect2.Type) ValEncoder
+	CreateDecoder(typ reflect2.Type) ValDecoder
+	CreateEncoder(typ reflect2.Type) ValEncoder
+	DecorateDecoder(typ reflect2.Type, decoder ValDecoder) ValDecoder
+	DecorateEncoder(typ reflect2.Type, encoder ValEncoder) ValEncoder
+}
+
+// DummyExtension embed this type get dummy implementation for all methods of Extension
+type DummyExtension struct {
+}
+
+// UpdateStructDescriptor No-op
+func (extension *DummyExtension) UpdateStructDescriptor(structDescriptor *StructDescriptor) {
+}
+
+// CreateMapKeyDecoder No-op
+func (extension *DummyExtension) CreateMapKeyDecoder(typ reflect2.Type) ValDecoder {
+	return nil
+}
+
+// CreateMapKeyEncoder No-op
+func (extension *DummyExtension) CreateMapKeyEncoder(typ reflect2.Type) ValEncoder {
+	return nil
+}
+
+// CreateDecoder No-op
+func (extension *DummyExtension) CreateDecoder(typ reflect2.Type) ValDecoder {
+	return nil
+}
+
+// CreateEncoder No-op
+func (extension *DummyExtension) CreateEncoder(typ reflect2.Type) ValEncoder {
+	return nil
+}
+
+// DecorateDecoder No-op
+func (extension *DummyExtension) DecorateDecoder(typ reflect2.Type, decoder ValDecoder) ValDecoder {
+	return decoder
+}
+
+// DecorateEncoder No-op
+func (extension *DummyExtension) DecorateEncoder(typ reflect2.Type, encoder ValEncoder) ValEncoder {
+	return encoder
+}
+
+type EncoderExtension map[reflect2.Type]ValEncoder
+
+// UpdateStructDescriptor No-op
+func (extension EncoderExtension) UpdateStructDescriptor(structDescriptor *StructDescriptor) {
+}
+
+// CreateDecoder No-op
+func (extension EncoderExtension) CreateDecoder(typ reflect2.Type) ValDecoder {
+	return nil
+}
+
+// CreateEncoder get encoder from map
+func (extension EncoderExtension) CreateEncoder(typ reflect2.Type) ValEncoder {
+	return extension[typ]
+}
+
+// CreateMapKeyDecoder No-op
+func (extension EncoderExtension) CreateMapKeyDecoder(typ reflect2.Type) ValDecoder {
+	return nil
+}
+
+// CreateMapKeyEncoder No-op
+func (extension EncoderExtension) CreateMapKeyEncoder(typ reflect2.Type) ValEncoder {
+	return nil
+}
+
+// DecorateDecoder No-op
+func (extension EncoderExtension) DecorateDecoder(typ reflect2.Type, decoder ValDecoder) ValDecoder {
+	return decoder
+}
+
+// DecorateEncoder No-op
+func (extension EncoderExtension) DecorateEncoder(typ reflect2.Type, encoder ValEncoder) ValEncoder {
+	return encoder
+}
+
+type DecoderExtension map[reflect2.Type]ValDecoder
+
+// UpdateStructDescriptor No-op
+func (extension DecoderExtension) UpdateStructDescriptor(structDescriptor *StructDescriptor) {
+}
+
+// CreateMapKeyDecoder No-op
+func (extension DecoderExtension) CreateMapKeyDecoder(typ reflect2.Type) ValDecoder {
+	return nil
+}
+
+// CreateMapKeyEncoder No-op
+func (extension DecoderExtension) CreateMapKeyEncoder(typ reflect2.Type) ValEncoder {
+	return nil
+}
+
+// CreateDecoder get decoder from map
+func (extension DecoderExtension) CreateDecoder(typ reflect2.Type) ValDecoder {
+	return extension[typ]
+}
+
+// CreateEncoder No-op
+func (extension DecoderExtension) CreateEncoder(typ reflect2.Type) ValEncoder {
+	return nil
+}
+
+// DecorateDecoder No-op
+func (extension DecoderExtension) DecorateDecoder(typ reflect2.Type, decoder ValDecoder) ValDecoder {
+	return decoder
+}
+
+// DecorateEncoder No-op
+func (extension DecoderExtension) DecorateEncoder(typ reflect2.Type, encoder ValEncoder) ValEncoder {
+	return encoder
+}
+
+type funcDecoder struct {
+	fun DecoderFunc
+}
+
+func (decoder *funcDecoder) Decode(ptr unsafe.Pointer, iter *Iterator) {
+	decoder.fun(ptr, iter)
+}
+
+type funcEncoder struct {
+	fun         EncoderFunc
+	isEmptyFunc func(ptr unsafe.Pointer) bool
+}
+
+func (encoder *funcEncoder) Encode(ptr unsafe.Pointer, stream *Stream) {
+	encoder.fun(ptr, stream)
+}
+
+func (encoder *funcEncoder) IsEmpty(ptr unsafe.Pointer) bool {
+	if encoder.isEmptyFunc == nil {
+		return false
+	}
+	return encoder.isEmptyFunc(ptr)
+}
+
+// DecoderFunc the function form of TypeDecoder
+type DecoderFunc func(ptr unsafe.Pointer, iter *Iterator)
+
+// EncoderFunc the function form of TypeEncoder
+type EncoderFunc func(ptr unsafe.Pointer, stream *Stream)
+
+// RegisterTypeDecoderFunc register TypeDecoder for a type with function
+func RegisterTypeDecoderFunc(typ string, fun DecoderFunc) {
+	typeDecoders[typ] = &funcDecoder{fun}
+}
+
+// RegisterTypeDecoder register TypeDecoder for a typ
+func RegisterTypeDecoder(typ string, decoder ValDecoder) {
+	typeDecoders[typ] = decoder
+}
+
+// RegisterFieldDecoderFunc register TypeDecoder for a struct field with function
+func RegisterFieldDecoderFunc(typ string, field string, fun DecoderFunc) {
+	RegisterFieldDecoder(typ, field, &funcDecoder{fun})
+}
+
+// RegisterFieldDecoder register TypeDecoder for a struct field
+func RegisterFieldDecoder(typ string, field string, decoder ValDecoder) {
+	fieldDecoders[fmt.Sprintf("%s/%s", typ, field)] = decoder
+}
+
+// RegisterTypeEncoderFunc register TypeEncoder for a type with encode/isEmpty function
+func RegisterTypeEncoderFunc(typ string, fun EncoderFunc, isEmptyFunc func(unsafe.Pointer) bool) {
+	typeEncoders[typ] = &funcEncoder{fun, isEmptyFunc}
+}
+
+// RegisterTypeEncoder register TypeEncoder for a type
+func RegisterTypeEncoder(typ string, encoder ValEncoder) {
+	typeEncoders[typ] = encoder
+}
+
+// RegisterFieldEncoderFunc register TypeEncoder for a struct field with encode/isEmpty function
+func RegisterFieldEncoderFunc(typ string, field string, fun EncoderFunc, isEmptyFunc func(unsafe.Pointer) bool) {
+	RegisterFieldEncoder(typ, field, &funcEncoder{fun, isEmptyFunc})
+}
+
+// RegisterFieldEncoder register TypeEncoder for a struct field
+func RegisterFieldEncoder(typ string, field string, encoder ValEncoder) {
+	fieldEncoders[fmt.Sprintf("%s/%s", typ, field)] = encoder
+}
+
+// RegisterExtension register extension
+func RegisterExtension(extension Extension) {
+	extensions = append(extensions, extension)
+}
+
+func getTypeDecoderFromExtension(ctx *ctx, typ reflect2.Type) ValDecoder {
+	decoder := _getTypeDecoderFromExtension(ctx, typ)
+	if decoder != nil {
+		for _, extension := range extensions {
+			decoder = extension.DecorateDecoder(typ, decoder)
+		}
+		decoder = ctx.decoderExtension.DecorateDecoder(typ, decoder)
+		for _, extension := range ctx.extraExtensions {
+			decoder = extension.DecorateDecoder(typ, decoder)
+		}
+	}
+	return decoder
+}
+func _getTypeDecoderFromExtension(ctx *ctx, typ reflect2.Type) ValDecoder {
+	for _, extension := range extensions {
+		decoder := extension.CreateDecoder(typ)
+		if decoder != nil {
+			return decoder
+		}
+	}
+	decoder := ctx.decoderExtension.CreateDecoder(typ)
+	if decoder != nil {
+		return decoder
+	}
+	for _, extension := range ctx.extraExtensions {
+		decoder := extension.CreateDecoder(typ)
+		if decoder != nil {
+			return decoder
+		}
+	}
+	typeName := typ.String()
+	decoder = typeDecoders[typeName]
+	if decoder != nil {
+		return decoder
+	}
+	if typ.Kind() == reflect.Ptr {
+		ptrType := typ.(*reflect2.UnsafePtrType)
+		decoder := typeDecoders[ptrType.Elem().String()]
+		if decoder != nil {
+			return &OptionalDecoder{ptrType.Elem(), decoder}
+		}
+	}
+	return nil
+}
+
+func getTypeEncoderFromExtension(ctx *ctx, typ reflect2.Type) ValEncoder {
+	encoder := _getTypeEncoderFromExtension(ctx, typ)
+	if encoder != nil {
+		for _, extension := range extensions {
+			encoder = extension.DecorateEncoder(typ, encoder)
+		}
+		encoder = ctx.encoderExtension.DecorateEncoder(typ, encoder)
+		for _, extension := range ctx.extraExtensions {
+			encoder = extension.DecorateEncoder(typ, encoder)
+		}
+	}
+	return encoder
+}
+
+func _getTypeEncoderFromExtension(ctx *ctx, typ reflect2.Type) ValEncoder {
+	for _, extension := range extensions {
+		encoder := extension.CreateEncoder(typ)
+		if encoder != nil {
+			return encoder
+		}
+	}
+	encoder := ctx.encoderExtension.CreateEncoder(typ)
+	if encoder != nil {
+		return encoder
+	}
+	for _, extension := range ctx.extraExtensions {
+		encoder := extension.CreateEncoder(typ)
+		if encoder != nil {
+			return encoder
+		}
+	}
+	typeName := typ.String()
+	encoder = typeEncoders[typeName]
+	if encoder != nil {
+		return encoder
+	}
+	if typ.Kind() == reflect.Ptr {
+		typePtr := typ.(*reflect2.UnsafePtrType)
+		encoder := typeEncoders[typePtr.Elem().String()]
+		if encoder != nil {
+			return &OptionalEncoder{encoder}
+		}
+	}
+	return nil
+}
+
+func describeStruct(ctx *ctx, typ reflect2.Type) *StructDescriptor {
+	structType := typ.(*reflect2.UnsafeStructType)
+	embeddedBindings := []*Binding{}
+	bindings := []*Binding{}
+	for i := 0; i < structType.NumField(); i++ {
+		field := structType.Field(i)
+		tag, hastag := field.Tag().Lookup(ctx.getTagKey())
+		if ctx.onlyTaggedField && !hastag && !field.Anonymous() {
+			continue
+		}
+		tagParts := strings.Split(tag, ",")
+		if tag == "-" {
+			continue
+		}
+		if field.Anonymous() && (tag == "" || tagParts[0] == "") {
+			if field.Type().Kind() == reflect.Struct {
+				structDescriptor := describeStruct(ctx, field.Type())
+				for _, binding := range structDescriptor.Fields {
+					binding.levels = append([]int{i}, binding.levels...)
+					omitempty := binding.Encoder.(*structFieldEncoder).omitempty
+					binding.Encoder = &structFieldEncoder{field, binding.Encoder, omitempty}
+					binding.Decoder = &structFieldDecoder{field, binding.Decoder}
+					embeddedBindings = append(embeddedBindings, binding)
+				}
+				continue
+			} else if field.Type().Kind() == reflect.Ptr {
+				ptrType := field.Type().(*reflect2.UnsafePtrType)
+				if ptrType.Elem().Kind() == reflect.Struct {
+					structDescriptor := describeStruct(ctx, ptrType.Elem())
+					for _, binding := range structDescriptor.Fields {
+						binding.levels = append([]int{i}, binding.levels...)
+						omitempty := binding.Encoder.(*structFieldEncoder).omitempty
+						binding.Encoder = &dereferenceEncoder{binding.Encoder}
+						binding.Encoder = &structFieldEncoder{field, binding.Encoder, omitempty}
+						binding.Decoder = &dereferenceDecoder{ptrType.Elem(), binding.Decoder}
+						binding.Decoder = &structFieldDecoder{field, binding.Decoder}
+						embeddedBindings = append(embeddedBindings, binding)
+					}
+					continue
+				}
+			}
+		}
+		fieldNames := calcFieldNames(field.Name(), tagParts[0], tag)
+		fieldCacheKey := fmt.Sprintf("%s/%s", typ.String(), field.Name())
+		decoder := fieldDecoders[fieldCacheKey]
+		if decoder == nil {
+			decoder = decoderOfType(ctx.append(field.Name()), field.Type())
+		}
+		encoder := fieldEncoders[fieldCacheKey]
+		if encoder == nil {
+			encoder = encoderOfType(ctx.append(field.Name()), field.Type())
+		}
+		binding := &Binding{
+			Field:     field,
+			FromNames: fieldNames,
+			ToNames:   fieldNames,
+			Decoder:   decoder,
+			Encoder:   encoder,
+		}
+		binding.levels = []int{i}
+		bindings = append(bindings, binding)
+	}
+	return createStructDescriptor(ctx, typ, bindings, embeddedBindings)
+}
+func createStructDescriptor(ctx *ctx, typ reflect2.Type, bindings []*Binding, embeddedBindings []*Binding) *StructDescriptor {
+	structDescriptor := &StructDescriptor{
+		Type:   typ,
+		Fields: bindings,
+	}
+	for _, extension := range extensions {
+		extension.UpdateStructDescriptor(structDescriptor)
+	}
+	ctx.encoderExtension.UpdateStructDescriptor(structDescriptor)
+	ctx.decoderExtension.UpdateStructDescriptor(structDescriptor)
+	for _, extension := range ctx.extraExtensions {
+		extension.UpdateStructDescriptor(structDescriptor)
+	}
+	processTags(structDescriptor, ctx.frozenConfig)
+	// merge normal & embedded bindings & sort with original order
+	allBindings := sortableBindings(append(embeddedBindings, structDescriptor.Fields...))
+	sort.Sort(allBindings)
+	structDescriptor.Fields = allBindings
+	return structDescriptor
+}
+
+type sortableBindings []*Binding
+
+func (bindings sortableBindings) Len() int {
+	return len(bindings)
+}
+
+func (bindings sortableBindings) Less(i, j int) bool {
+	left := bindings[i].levels
+	right := bindings[j].levels
+	k := 0
+	for {
+		if left[k] < right[k] {
+			return true
+		} else if left[k] > right[k] {
+			return false
+		}
+		k++
+	}
+}
+
+func (bindings sortableBindings) Swap(i, j int) {
+	bindings[i], bindings[j] = bindings[j], bindings[i]
+}
+
+func processTags(structDescriptor *StructDescriptor, cfg *frozenConfig) {
+	for _, binding := range structDescriptor.Fields {
+		shouldOmitEmpty := false
+		tagParts := strings.Split(binding.Field.Tag().Get(cfg.getTagKey()), ",")
+		for _, tagPart := range tagParts[1:] {
+			if tagPart == "omitempty" {
+				shouldOmitEmpty = true
+			} else if tagPart == "string" {
+				if binding.Field.Type().Kind() == reflect.String {
+					binding.Decoder = &stringModeStringDecoder{binding.Decoder, cfg}
+					binding.Encoder = &stringModeStringEncoder{binding.Encoder, cfg}
+				} else {
+					binding.Decoder = &stringModeNumberDecoder{binding.Decoder}
+					binding.Encoder = &stringModeNumberEncoder{binding.Encoder}
+				}
+			}
+		}
+		binding.Decoder = &structFieldDecoder{binding.Field, binding.Decoder}
+		binding.Encoder = &structFieldEncoder{binding.Field, binding.Encoder, shouldOmitEmpty}
+	}
+}
+
+func calcFieldNames(originalFieldName string, tagProvidedFieldName string, wholeTag string) []string {
+	// ignore?
+	if wholeTag == "-" {
+		return []string{}
+	}
+	// rename?
+	var fieldNames []string
+	if tagProvidedFieldName == "" {
+		fieldNames = []string{originalFieldName}
+	} else {
+		fieldNames = []string{tagProvidedFieldName}
+	}
+	// private?
+	isNotExported := unicode.IsLower(rune(originalFieldName[0]))
+	if isNotExported {
+		fieldNames = []string{}
+	}
+	return fieldNames
+}