ctxsync | package implements the standard library | Caching library

<sub>( The O/P MCVE-problem definition creeps further - yet the problem of coordination, be it prioritised or not, of {sensors|actors}-control-systems, the more the systems designed with a use of distributed autonomous agents is professionally very complex and easy to make defective "shortcuts" or get into a system-wide blocking-state

Best first read at least this about ZeroMQ Hierarchy in Less Than Five Seconds and this about mutual dead-lock blocking

Reading the fabulous Pieter HINTJENS' book "Code Connected: Volume 1" is of immense value for any system designer )</sub>

_{"...seams quite interesting as it implements the async already, so I could just add the async zmq as I did. am I wrong?"}

Yes, there is no "just add async" shortcut, control-systems are very interesting discipline, but rather a complex one. Always. Sorry to have to hear that straight. Some complexities might get hidden from user in schoolbook examples or in trivial makers-projects. The hammer then comes right on trying steps to extend them, by just adding one or a few more trivial features. The complexity suddenly gets to the surface, not seen before.

Put the formal map on a full-screen editor so as to see the bigger picture of all mutually conflicting dependencies and competing loops-of-control. Latency is the easy part. Several places of risks of un-resolvable deadlock blocking is the core one. ZeroMQ, since v2.x had tooling for avoiding some of these, software designer has the responsibility to properly mitigate all the others. Control systems ( robotics or other ) have to proof such robustness and resilience to errors and safely "survive" also all "external" mishaps.

The best point to start with is the old golden rule as expressed in assembly language directive on row 1: