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: checkinit.go
    path of file: ./repos/docker-ce/components/cli/vendor/google.golang.org/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/internal/errors"
	"google.golang.org/protobuf/reflect/protoreflect"
	"google.golang.org/protobuf/runtime/protoiface"
)

// CheckInitialized returns an error if any required fields in m are not set.
func CheckInitialized(m Message) error {
	// Treat a nil message interface as an "untyped" empty message,
	// which we assume to have no required fields.
	if m == nil {
		return nil
	}

	return checkInitialized(m.ProtoReflect())
}

// CheckInitialized returns an error if any required fields in m are not set.
func checkInitialized(m protoreflect.Message) error {
	if methods := protoMethods(m); methods != nil && methods.CheckInitialize
    
func checkInitializedSlow(m protoreflect.Message) error {
	md := m.Descriptor()
	fds := md.Fields()
	for i, nums := 0, md.RequiredNumbers(); i < nums.Len(); i++ {
		fd := fds.ByNumber(nums.Get(i))
		if !m.Has(fd) {
			return errors.RequiredNotSet(string(fd.FullName()))
		}
	}
	var err error
	m.Range(func(fd protoreflect.FieldDescriptor, v protoreflect.Value) bool {
		switch {
		case fd.IsList():
			if fd.Message() == nil {
				return true
			}
			for i, list := 0, v.List(); i < list.Len() && err == nil; i++ {
				err = checkInitialized(list.Get(i).Message())
			}
		case fd.IsMap():
			if fd.MapValue().Message() == nil {
				return true
			}
			v.Map().Range(func(key protoreflect.MapKey, v protoreflect.Value) bool {
				err = checkInitialized(v.Message())
				return err == nil
			})
		default:
			if fd.Message() == nil {
				return true
			}
			err = checkInitialized(v.Message())
		}
		return err == nil
	})
	return err
}