> There is a (mostly) reliable way ...

I forgot to mention that there is a small catch: some constant input
ports (specifically an "all zeros" port) might cause initialization
errors for some PRNGs.  This is a general issue with random port
initialization, though.  The next draft of this SRFI will exclude
all-zeros from the arbitrary-data-initialization requirement, since
it's known to be a problem (e.g. for xoshiro generators).

--
Wolfgang Corcoran-Mathe  <xxxxxx@sigwinch.xyz>