1) How do you ensure that the images are not cached to compare the load times in the demo?
2) Do you expect the load to ever be significant enough that dropping messages will become necessary? If so, how are you planning to handle that?
1- Both apps do the same client-side caching, with no server-side caching. The Nextop protocol is able to get bytes down faster from raw requests than direct HTTP (limited to 2 concurrent connections). An update to the proxy will be coming out soon that does caching like a proper CDN, which will be a big win. Look out for other performance improvements this week too (I can discuss more if you want).
The bottom line is that Nextop ImageView loads your images >=HTTP/2 with zero changes to your backend. This is a huge win for developers wanting to make the switch now.
2-The client supports prioritization+multiplexing to handle that. More important messages will always be sent at the head of the line, regardless of the backlog. The important thing to remember is that the connection is a bunch of pipelines (Nextop calls them groups), where messages in each pipeline get sent in order, and pipelines get merged into a single stream out/in.
Now a lot of messages that drive views like GETs aren't necessary when the view goes off the screen. Nextop handles that case for you with some nice integrations between view and requests, which can help the backlog. If your app needs to cancel/merge messages like, for example, an app sending a stream of geo updates, Nextop supports canceling a message which will remove from the queue if present. "canelSend(p); send(p = current);" one pattern to manage the backlog for messages that can be replaced with newer versions.
We're rolling out some prefetching/offline stuff in the next couple weeks that will really highlight this.
Now the memory impact of the backlog is important. I think letting Nextop abstract that and improve is better than pushing memory issues into the rest of the app. In general the Nextop philosophy is a simple API that does the right thing with a broad range of input/output values. All the special cases will go into the library to save developers' headaches. Nextop eventually reaches zero memory use and gives you the tools to manage memory/bandwidth use by crafting how your app sends messages. For example, downsampling a camera photo for upload is a one-liner in Nextop.