presto-main/src/main/java/io/prestosql/operator/ExchangeClient.java/ExchangeClientCallback/addPages
class ExchangeClientCallback:        @Override
        public boolean addPages(HttpPageBufferClient client, List<SerializedPage> pages)
        {
            requireNonNull(client, "client is null");
            requireNonNull(pages, "pages is null");
            return ExchangeClient.this.addPages(pages);
        }