Rpcd file timeout too short (just 3 seconds)

Is there a way to increase this timeout via configuration or environment?
ubus default timeout is 30 seconds so what is the reason of such a short hardcoded timeout for rpcd file?

Applying a patch with your build tree could change it. That it's a define suggests its unlikely a "tunable"

#define RPC_FILE_MAX_RUNTIME    (3 * 1000)

Curious as to why a 30-second timeout is insufficient for an RPC interaction that typically should take a small fraction of a second.

30 seconds is enough for most calls. I mentioned this to emphasize the difference between timeouts in rpcd plugin and ubus itself.
Thanks for advice. Will create patch.