public Builder headerInjector(HeaderInjector headerInjector) {
            this.headerInjector = checkNotNull(headerInjector);
            return this;
        }
Add headers along the request to the server

@param headerInjector to inject header base on url
@return a builder
dkplayer-videocache/src/main/java/com/danikula/videocache/HttpProxyCacheServer.java