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: file_cache.go
    path of file: ./repos/oak/audio
    
    the code of the file until where you have to start completion: package audio

import (
	"path/filepath"
	"sync"

	"github.com/oakmound/oak/v4/audio/pcm"
)

// DefaultCache is the receiver for package level loading operations.
var DefaultCache = NewCache()

// Cache
    
func (c *Cache) setLoaded(file string, r pcm.Reader) {
	// This ReadAll and .Copy() on Cache.Read ensure that multiple loads from the cache do not
	// change the data that will be read on future reads.
	br := ReadAll(r)
	c.mu.Lock()
	c.data[file] = br
	c.data[filepath.Base(file)] = br
	c.mu.Unlock()
}