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: termenv_windows.go
    path of file: ./repos/termenv
    
    the code of the file until where you have to start completion: //go:build windows
// +build windows

package termenv

import (
	"fmt"
	"os"
	"strconv"

	"golang.org/x/sys/windows"
)

func (o *Output) ColorProfile() Profile {
	if !o.isTTY() {
		return Ascii
	}

	if o.environ.Getenv("ConEmuANSI") == "ON" {
		return TrueColor
	}

	winVersion, _, buildNumber := windows.RtlGetNtVersionNumbers()
	if buildNumber < 
    
func (o *Output) ColorProfile() Profile {
	if !o.isTTY() {
		return Ascii
	}

	if o.environ.Getenv("ConEmuANSI") == "ON" {
		return TrueColor
	}

	winVersion, _, buildNumber := windows.RtlGetNtVersionNumbers()
	if buildNumber < 10586 || winVersion < 10 {
		// No ANSI support before Windows 10 build 10586.
		if o.environ.Getenv("ANSICON") != "" {
			conVersion := o.environ.Getenv("ANSICON_VER")
			cv, err := strconv.ParseInt(conVersion, 10, 64)
			if err != nil || cv < 181 {
				// No 8 bit color support before v1.81 release.
				return ANSI
			}

			return ANSI256
		}

		return Ascii
	}
	if buildNumber < 14931 {
		// No true color support before build 14931.
		return ANSI256
	}

	return TrueColor
}