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: yaml.go
    path of file: ./repos/lazygit/vendor/gopkg.in/yaml.v3
    
    the code of the file until where you have to start completion: //
// Copyright (c) 2011-2019 Canonical Ltd
//
// 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
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// Package yaml implements YAML support for the Go language.
//
// Source code and other details for the project are available at GitHub:
//
//   https://github.com/go-yaml/yaml
//
package yaml

import (
	"errors"
	"fmt"
	"io"
	"reflect"
	"strings"
	"sync"
	"unicode/utf8"
)

// The Unmarshaler interface may be implemented by types to customize their
// behavior when being unmarshaled from a YAML document.
type Unmarshaler interface {
	UnmarshalYAML(value *Node) error
}

type obsoleteUnmarshaler interface {
	UnmarshalYAML(unmarshal func(interface{}) error) error
}

// The Marshaler interface may be implemented by types to customize their
// behavior when being marshaled into a YAML document. The returned value
// is marshaled in place of the original value implementing Marshaler.
//
// If an error is returned by MarshalYAML, the marshaling procedure stops
// and returns with the provided error.
type Marshaler interface {
	MarshalYAML() (interface{}, error)
}

// Unmarshal decodes the first document found within the in byte slice
// and assigns decoded values into the out value.
//
// Maps and pointers (to a struct, string, int, etc) are accepted as out
// values. If an internal pointer within a struct is not initialized,
// the yaml package will initialize it if necessary for unmarshalling
// the provided data. The out parameter must not be nil.
//
// The type of the decoded values should be compatible with the respective
// values in out. If one or more values cannot be decoded due to a type
// mismatches, decoding continues partially until the end of the YAML
// content, and a *yaml.TypeError is returned with details for all
// missed values.
//
// Struct fields are only unmarshalled if they are exported (have an
// upper case first letter), and are unmarshalled using the field name
// lowercased as the default key. Custom keys may be defined via the
// "yaml" name in the field tag: the content preceding the first comma
// is used as the key, and the following comma-separated options are
// used to tweak the marshalling process (see Marshal).
// Conflicting names result in a runtime error.
//
// For example:
//
//     type T struct {
//         F int `yaml:"a,omitempty"`
//         B int
//     }
//     var t T
//     yaml.Unmarshal([]byte("a: 1\nb: 2"), &t)
//
// See the documentation of Marshal for the format of tags and a list of
// supported tag o
    
func getStructInfo(st reflect.Type) (*structInfo, error) {
	fieldMapMutex.RLock()
	sinfo, found := structMap[st]
	fieldMapMutex.RUnlock()
	if found {
		return sinfo, nil
	}

	n := st.NumField()
	fieldsMap := make(map[string]fieldInfo)
	fieldsList := make([]fieldInfo, 0, n)
	inlineMap := -1
	inlineUnmarshalers := [][]int(nil)
	for i := 0; i != n; i++ {
		field := st.Field(i)
		if field.PkgPath != "" && !field.Anonymous {
			continue // Private field
		}

		info := fieldInfo{Num: i}

		tag := field.Tag.Get("yaml")
		if tag == "" && strings.Index(string(field.Tag), ":") < 0 {
			tag = string(field.Tag)
		}
		if tag == "-" {
			continue
		}

		inline := false
		fields := strings.Split(tag, ",")
		if len(fields) > 1 {
			for _, flag := range fields[1:] {
				switch flag {
				case "omitempty":
					info.OmitEmpty = true
				case "flow":
					info.Flow = true
				case "inline":
					inline = true
				default:
					return nil, errors.New(fmt.Sprintf("unsupported flag %q in tag %q of type %s", flag, tag, st))
				}
			}
			tag = fields[0]
		}

		if inline {
			switch field.Type.Kind() {
			case reflect.Map:
				if inlineMap >= 0 {
					return nil, errors.New("multiple ,inline maps in struct " + st.String())
				}
				if field.Type.Key() != reflect.TypeOf("") {
					return nil, errors.New("option ,inline needs a map with string keys in struct " + st.String())
				}
				inlineMap = info.Num
			case reflect.Struct, reflect.Ptr:
				ftype := field.Type
				for ftype.Kind() == reflect.Ptr {
					ftype = ftype.Elem()
				}
				if ftype.Kind() != reflect.Struct {
					return nil, errors.New("option ,inline may only be used on a struct or map field")
				}
				if reflect.PtrTo(ftype).Implements(unmarshalerType) {
					inlineUnmarshalers = append(inlineUnmarshalers, []int{i})
				} else {
					sinfo, err := getStructInfo(ftype)
					if err != nil {
						return nil, err
					}
					for _, index := range sinfo.InlineUnmarshalers {
						inlineUnmarshalers = append(inlineUnmarshalers, append([]int{i}, index...))
					}
					for _, finfo := range sinfo.FieldsList {
						if _, found := fieldsMap[finfo.Key]; found {
							msg := "duplicated key '" + finfo.Key + "' in struct " + st.String()
							return nil, errors.New(msg)
						}
						if finfo.Inline == nil {
							finfo.Inline = []int{i, finfo.Num}
						} else {
							finfo.Inline = append([]int{i}, finfo.Inline...)
						}
						finfo.Id = len(fieldsList)
						fieldsMap[finfo.Key] = finfo
						fieldsList = append(fieldsList, finfo)
					}
				}
			default:
				return nil, errors.New("option ,inline may only be used on a struct or map field")
			}
			continue
		}

		if tag != "" {
			info.Key = tag
		} else {
			info.Key = strings.ToLower(field.Name)
		}

		if _, found = fieldsMap[info.Key]; found {
			msg := "duplicated key '" + info.Key + "' in struct " + st.String()
			return nil, errors.New(msg)
		}

		info.Id = len(fieldsList)
		fieldsList = append(fieldsList, info)
		fieldsMap[info.Key] = info
	}

	sinfo = &structInfo{
		FieldsMap:          fieldsMap,
		FieldsList:         fieldsList,
		InlineMap:          inlineMap,
		InlineUnmarshalers: inlineUnmarshalers,
	}

	fieldMapMutex.Lock()
	structMap[st] = sinfo
	fieldMapMutex.Unlock()
	return sinfo, nil
}