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: gotrack.go
    path of file: ./repos/goldfish/vendor/golang.org/x/net/http2
    
    the code of the file until where you have to start completion: // Copyright 2014 The Go Author
    
func curGoroutineID() uint64 {
	bp := littleBuf.Get().(*[]byte)
	defer littleBuf.Put(bp)
	b := *bp
	b = b[:runtime.Stack(b, false)]
	// Parse the 4707 out of "goroutine 4707 ["
	b = bytes.TrimPrefix(b, goroutineSpace)
	i := bytes.IndexByte(b, ' ')
	if i < 0 {
		panic(fmt.Sprintf("No space found in %q", b))
	}
	b = b[:i]
	n, err := parseUintBytes(b, 10, 64)
	if err != nil {
		panic(fmt.Sprintf("Failed to parse goroutine ID out of %q: %v", b, err))
	}
	return n
}