func NewDocumentBuilder() *DocumentBuilder {
	return (&DocumentBuilder{}).startDocument()
}
NewDocumentBuilder creates a new DocumentBuilder
package bsoncore
import (
	"go.mongodb.org/mongo-driver/bson/bsontype"
	"go.mongodb.org/mongo-driver/bson/primitive"
)
type DocumentBuilder struct {
	doc     []byte
	indexes []int32
}
func (db *DocumentBuilder) startDocument() *DocumentBuilder {
	var index int32
	index, db.doc = AppendDocumentStart(db.doc)
	db.indexes = append(db.indexes, index)
	return db
}