add vendor directory

vendor/github.com/modern-go/reflect2/safe_struct.go

@@ -0,0 +1,29 @@
+package reflect2
+
+type safeStructType struct {
+	safeType
+}
+
+func (type2 *safeStructType) FieldByName(name string) StructField {
+	field, found := type2.Type.FieldByName(name)
+	if !found {
+		panic("field " + name + " not found")
+	}
+	return &safeField{StructField: field}
+}
+
+func (type2 *safeStructType) Field(i int) StructField {
+	return &safeField{StructField: type2.Type.Field(i)}
+}
+
+func (type2 *safeStructType) FieldByIndex(index []int) StructField {
+	return &safeField{StructField: type2.Type.FieldByIndex(index)}
+}
+
+func (type2 *safeStructType) FieldByNameFunc(match func(string) bool) StructField {
+	field, found := type2.Type.FieldByNameFunc(match)
+	if !found {
+		panic("field match condition not found in " + type2.Type.String())
+	}
+	return &safeField{StructField: field}
+}