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: features.go
    path of file: ./repos/gotosocial/vendor/github.com/bytedance/sonic/internal/cpu
    
    the code of the file until where you have to start completion: /*
 * Copyright 2021 ByteDance Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may no
    
func init() {
    switch v := os.Getenv("SONIC_MODE"); v {
        case ""       : break
        case "auto"   : break
        case "noavx"  : HasAVX = false; fallthrough
        case "noavx2" : HasAVX2 = false
        default       : panic(fmt.Sprintf("invalid mode: '%s', should be one of 'auto', 'noavx', 'noavx2'", v))
    }
}