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: diskv.go
    path of file: ./repos/devspace/vendor/github.com/peterbourgon/diskv
    
    the code of the file until where you have to start completion: // Diskv (disk-vee) is a simple, persistent, key-value store.
// It stores all data flatly on the filesystem.

package di
    
func (d *Diskv) KeysPrefix(prefix string, cancel <-chan struct{}) <-chan string {
	var prepath string
	if prefix == "" {
		prepath = d.BasePath
	} else {
		prepath = d.pathFor(prefix)
	}
	c := make(chan string)
	go func() {
		filepath.Walk(prepath, walker(c, prefix, cancel))
		close(c)
	}()
	return c
}