public void handle(RestRequest restRequest, RestResponseChannel restResponseChannel,
      Callback<ReadableStreamChannel> callback) {
    new CallbackChain(restRequest, restResponseChannel, callback).start();
  }
Asynchronously get account metadata.
@param restRequest the {@link RestRequest} that contains the request parameters and body.
@param restResponseChannel the {@link RestResponseChannel} where headers should be set.
@param callback the {@link Callback} to invoke when the response is ready (or if there is an exception).
ambry-frontend/src/main/java/com/github/ambry/frontend/NamedBlobListHandler.java