Pacing is enforced by httr2::req_throttle() inside the shared
request builder (see vt_request), tunable via
options(virustotal.requests_per_minute=) and switchable via
options(virustotal.throttle=). What lives here is a passive log of
request times, kept so virustotal_info() can report usage against
the public API's 4-per-minute allowance.
See also
Other rate limiting:
get_rate_limit_status(),
record_request(),
reset_rate_limit()