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: bucket_options.go
    path of file: ./repos/mongo-go-driver/mongo/integration/unified
    
    the code of the file until where you have to start completion: // Copyright (C) MongoDB, Inc. 2017-present.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may
// not use this file except in compliance with the License. You may obtain
// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0

package unified

import (
	"fmt"

	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/mongo/options"
)

// gridFSBucketOptions is a wrapper for *options.BucketOptions. This type implements the bson.Unmarshaler interface to
// convert BSON documents to a BucketOptions instance.
type gridFSBucketOptions struct {
	*options.BucketOptions
}

var _ bson.Unmarshaler = (*gridFSBucketOptions)(nil)

func (bo *gridFSBucketOptions) UnmarshalBSON(data []byte) error {
	var temp struct {
		Name      *string                `bson:"name"`
		ChunkSize *int32                 `bson:"chunkSizeBytes"`
		RC        *readConcern           `bson:"readConcern"`
		RP        *ReadPreference        `bson:"readPreference"`
		WC        *writeConcern          `bson:"writeConcern"`
		Extra     map[string]interface{} `bson:",inline"`
	}
	if err := bson
    
func (bo *gridFSBucketOptions) UnmarshalBSON(data []byte) error {
	var temp struct {
		Name      *string                `bson:"name"`
		ChunkSize *int32                 `bson:"chunkSizeBytes"`
		RC        *readConcern           `bson:"readConcern"`
		RP        *ReadPreference        `bson:"readPreference"`
		WC        *writeConcern          `bson:"writeConcern"`
		Extra     map[string]interface{} `bson:",inline"`
	}
	if err := bson.Unmarshal(data, &temp); err != nil {
		return fmt.Errorf("error unmarshalling to temporary gridFSBucketOptions object: %w", err)
	}
	if len(temp.Extra) > 0 {
		return fmt.Errorf("unrecognized fields for gridFSBucketOptions: %v", mapKeys(temp.Extra))
	}

	bo.BucketOptions = options.GridFSBucket()
	if temp.Name != nil {
		bo.SetName(*temp.Name)
	}
	if temp.ChunkSize != nil {
		bo.SetChunkSizeBytes(*temp.ChunkSize)
	}
	if temp.RC != nil {
		bo.SetReadConcern(temp.RC.toReadConcernOption())
	}
	if temp.RP != nil {
		rp, err := temp.RP.ToReadPrefOption()
		if err != nil {
			return fmt.Errorf("error parsing read preference document: %w", err)
		}
		bo.SetReadPreference(rp)
	}
	if temp.WC != nil {
		wc, err := temp.WC.toWriteConcernOption()
		if err != nil {
			return fmt.Errorf("error parsing write concern document: %w", err)
		}
		bo.SetWriteConcern(wc)
	}
	return nil
}