You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: defaults.go
    path of file: ./repos/k6/vendor/github.com/golang/protobuf/proto
    
    the code of the file until where you have to start completion: // Copyright 2019 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 proto

import (
	"google.golang.org/protobuf/reflect/protoreflect"
)

// SetDefaults sets unpopulated scalar fields to their default values.
// Fields within a oneof are not set even if they have a default value.
// SetDefaults is recursively called upon any populated message fields.
func SetDefaults(m Message) {
	if m != nil {
		setDefaults(MessageReflect(m))
	}
}

func setDefaults(m protoreflect.Message) {
	fds := m.Descriptor().Fields()
	for i := 0; i < fds.Len(); i++ {
		fd := fds.Get(i)
		if !m.Has(fd) {
			if fd.HasDefault() && fd.ContainingOneof() == nil {
				v := fd
    
func setDefaults(m protoreflect.Message) {
	fds := m.Descriptor().Fields()
	for i := 0; i < fds.Len(); i++ {
		fd := fds.Get(i)
		if !m.Has(fd) {
			if fd.HasDefault() && fd.ContainingOneof() == nil {
				v := fd.Default()
				if fd.Kind() == protoreflect.BytesKind {
					v = protoreflect.ValueOf(append([]byte(nil), v.Bytes()...)) // copy the default bytes
				}
				m.Set(fd, v)
			}
			continue
		}
	}

	m.Range(func(fd protoreflect.FieldDescriptor, v protoreflect.Value) bool {
		switch {
		// Handle singular message.
		case fd.Cardinality() != protoreflect.Repeated:
			if fd.Message() != nil {
				setDefaults(m.Get(fd).Message())
			}
		// Handle list of messages.
		case fd.IsList():
			if fd.Message() != nil {
				ls := m.Get(fd).List()
				for i := 0; i < ls.Len(); i++ {
					setDefaults(ls.Get(i).Message())
				}
			}
		// Handle map of messages.
		case fd.IsMap():
			if fd.MapValue().Message() != nil {
				ms := m.Get(fd).Map()
				ms.Range(func(_ protoreflect.MapKey, v protoreflect.Value) bool {
					setDefaults(v.Message())
					return true
				})
			}
		}
		return true
	})
}