+ // How many bytes we need to have in the backlog before we start
+ // sending (in practice, we will then send all of them at once,
+ // and then start sending at the normal rate thereafter).
+ // This is basically to force a buffer on the client, which can help
+ // if the client expects us to be able to fill up the buffer much
+ // faster than realtime (ie., it expects a static file).
+ size_t prebuffering_bytes;
+