diff --git a/vendor/github.com/modern-go/reflect2/unsafe_map.go b/vendor/github.com/modern-go/reflect2/unsafe_map.go
new file mode 100644
index 0000000..f2e76e6
--- /dev/null
+++ b/vendor/github.com/modern-go/reflect2/unsafe_map.go
@@ -0,0 +1,138 @@
+package reflect2
+
+import (
+	"reflect"
+	"unsafe"
+)
+
+type UnsafeMapType struct {
+	unsafeType
+	pKeyRType  unsafe.Pointer
+	pElemRType unsafe.Pointer
+}
+
+func newUnsafeMapType(cfg *frozenConfig, type1 reflect.Type) MapType {
+	return &UnsafeMapType{
+		unsafeType: *newUnsafeType(cfg, type1),
+		pKeyRType:  unpackEFace(reflect.PtrTo(type1.Key())).data,
+		pElemRType: unpackEFace(reflect.PtrTo(type1.Elem())).data,
+	}
+}
+
+func (type2 *UnsafeMapType) IsNil(obj interface{}) bool {
+	if obj == nil {
+		return true
+	}
+	objEFace := unpackEFace(obj)
+	assertType("Type.IsNil argument 1", type2.ptrRType, objEFace.rtype)
+	return type2.UnsafeIsNil(objEFace.data)
+}
+
+func (type2 *UnsafeMapType) UnsafeIsNil(ptr unsafe.Pointer) bool {
+	if ptr == nil {
+		return true
+	}
+	return *(*unsafe.Pointer)(ptr) == nil
+}
+
+func (type2 *UnsafeMapType) LikePtr() bool {
+	return true
+}
+
+func (type2 *UnsafeMapType) Indirect(obj interface{}) interface{} {
+	objEFace := unpackEFace(obj)
+	assertType("MapType.Indirect argument 1", type2.ptrRType, objEFace.rtype)
+	return type2.UnsafeIndirect(objEFace.data)
+}
+
+func (type2 *UnsafeMapType) UnsafeIndirect(ptr unsafe.Pointer) interface{} {
+	return packEFace(type2.rtype, *(*unsafe.Pointer)(ptr))
+}
+
+func (type2 *UnsafeMapType) Key() Type {
+	return type2.cfg.Type2(type2.Type.Key())
+}
+
+func (type2 *UnsafeMapType) MakeMap(cap int) interface{} {
+	return packEFace(type2.ptrRType, type2.UnsafeMakeMap(cap))
+}
+
+func (type2 *UnsafeMapType) UnsafeMakeMap(cap int) unsafe.Pointer {
+	m := makeMapWithSize(type2.rtype, cap)
+	return unsafe.Pointer(&m)
+}
+
+func (type2 *UnsafeMapType) SetIndex(obj interface{}, key interface{}, elem interface{}) {
+	objEFace := unpackEFace(obj)
+	assertType("MapType.SetIndex argument 1", type2.ptrRType, objEFace.rtype)
+	keyEFace := unpackEFace(key)
+	assertType("MapType.SetIndex argument 2", type2.pKeyRType, keyEFace.rtype)
+	elemEFace := unpackEFace(elem)
+	assertType("MapType.SetIndex argument 3", type2.pElemRType, elemEFace.rtype)
+	type2.UnsafeSetIndex(objEFace.data, keyEFace.data, elemEFace.data)
+}
+
+func (type2 *UnsafeMapType) UnsafeSetIndex(obj unsafe.Pointer, key unsafe.Pointer, elem unsafe.Pointer) {
+	mapassign(type2.rtype, *(*unsafe.Pointer)(obj), key, elem)
+}
+
+func (type2 *UnsafeMapType) TryGetIndex(obj interface{}, key interface{}) (interface{}, bool) {
+	objEFace := unpackEFace(obj)
+	assertType("MapType.TryGetIndex argument 1", type2.ptrRType, objEFace.rtype)
+	keyEFace := unpackEFace(key)
+	assertType("MapType.TryGetIndex argument 2", type2.pKeyRType, keyEFace.rtype)
+	elemPtr := type2.UnsafeGetIndex(objEFace.data, keyEFace.data)
+	if elemPtr == nil {
+		return nil, false
+	}
+	return packEFace(type2.pElemRType, elemPtr), true
+}
+
+func (type2 *UnsafeMapType) GetIndex(obj interface{}, key interface{}) interface{} {
+	objEFace := unpackEFace(obj)
+	assertType("MapType.GetIndex argument 1", type2.ptrRType, objEFace.rtype)
+	keyEFace := unpackEFace(key)
+	assertType("MapType.GetIndex argument 2", type2.pKeyRType, keyEFace.rtype)
+	elemPtr := type2.UnsafeGetIndex(objEFace.data, keyEFace.data)
+	return packEFace(type2.pElemRType, elemPtr)
+}
+
+func (type2 *UnsafeMapType) UnsafeGetIndex(obj unsafe.Pointer, key unsafe.Pointer) unsafe.Pointer {
+	return mapaccess(type2.rtype, *(*unsafe.Pointer)(obj), key)
+}
+
+func (type2 *UnsafeMapType) Iterate(obj interface{}) MapIterator {
+	objEFace := unpackEFace(obj)
+	assertType("MapType.Iterate argument 1", type2.ptrRType, objEFace.rtype)
+	return type2.UnsafeIterate(objEFace.data)
+}
+
+func (type2 *UnsafeMapType) UnsafeIterate(obj unsafe.Pointer) MapIterator {
+	return &UnsafeMapIterator{
+		hiter:      mapiterinit(type2.rtype, *(*unsafe.Pointer)(obj)),
+		pKeyRType:  type2.pKeyRType,
+		pElemRType: type2.pElemRType,
+	}
+}
+
+type UnsafeMapIterator struct {
+	*hiter
+	pKeyRType  unsafe.Pointer
+	pElemRType unsafe.Pointer
+}
+
+func (iter *UnsafeMapIterator) HasNext() bool {
+	return iter.key != nil
+}
+
+func (iter *UnsafeMapIterator) Next() (interface{}, interface{}) {
+	key, elem := iter.UnsafeNext()
+	return packEFace(iter.pKeyRType, key), packEFace(iter.pElemRType, elem)
+}
+
+func (iter *UnsafeMapIterator) UnsafeNext() (unsafe.Pointer, unsafe.Pointer) {
+	key := iter.key
+	elem := iter.value
+	mapiternext(iter.hiter)
+	return key, elem
+}