Said method has a func parameter (called just f), which it receives as
rvalue ref and just uses as a reference. This means that if caller
doesn't keep the func alive, for_each_cql_result() will run into
use-after-free after the first suspention point. This is unexpected for
callers, who don't expect to have to keep something alive, which they
passed in with std::move().
Adjust the signature to take a value instead, value parameters are moved
to the coro frame and survive suspention points.
Adjust internal callers (query_internal()) the same way.
There are no known vulnerable external callers.
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