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: parser.go
    path of file: ./repos/fabio/vendor/gopkg.in/ini.v1
    
    the code of the file until where you have to start completion: // Copyright 2015 Unknwon
//
// 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, eith
    
func readKeyName(delimiters string, in []byte) (string, int, error) {
	line := string(in)

	// Check if key name surrounded by quotes.
	var keyQuote string
	if line[0] == '"' {
		if len(line) > 6 && line[0:3] == `"""` {
			keyQuote = `"""`
		} else {
			keyQuote = `"`
		}
	} else if line[0] == '`' {
		keyQuote = "`"
	}

	// Get out key name
	var endIdx int
	if len(keyQuote) > 0 {
		startIdx := len(keyQuote)
		// FIXME: fail case -> """"""name"""=value
		pos := strings.Index(line[startIdx:], keyQuote)
		if pos == -1 {
			return "", -1, fmt.Errorf("missing closing key quote: %s", line)
		}
		pos += startIdx

		// Find key-value delimiter
		i := strings.IndexAny(line[pos+startIdx:], delimiters)
		if i < 0 {
			return "", -1, ErrDelimiterNotFound{line}
		}
		endIdx = pos + i
		return strings.TrimSpace(line[startIdx:pos]), endIdx + startIdx + 1, nil
	}

	endIdx = strings.IndexAny(line, delimiters)
	if endIdx < 0 {
		return "", -1, ErrDelimiterNotFound{line}
	}
	return strings.TrimSpace(line[0:endIdx]), endIdx + 1, nil
}