libnginx-mod-nchan 1.13.6-2ubuntu1 (arm64 binary) in ubuntu bionic

 Nchan is a scalable, flexible pub/sub server for the modern web, It can be
 configured as a standalone server, or as a shim between your application and
 tens, thousands, or millions of live subscribers. It can buffer messages in
 memory, on-disk, or via Redis. All connections are handled asynchronously and
 distributed among any number of worker processes. It can also scale to many
 nginx server instances with Redis.
 .
 Full documentation available at https://nchan.slact.net