public String getProxyUrl(String url) {
        return getProxyUrl(url, true);
    }
Returns url that wrap original url and should be used for client (MediaPlayer, ExoPlayer, etc).
<p>
If file for this url is fully cached (it means method {@link #isCached(String)} returns {@code true})
then file:// uri to cached file will be returned.
<p>
Calling this method has same effect as calling {@link #getProxyUrl(String, boolean)} with 2nd parameter set to {@code true}.

@param url a url to file that should be cached.
@return a wrapped by proxy url if file is not fully cached or url pointed to cache file otherwise.
VideoCache/src/main/java/com/yc/videocache/HttpProxyCacheServer.java