UPDATE_RATE: Update the rate limit of an existing rate limited function
Description
UPDATE_RATE modifies an existing rate-limited function in place,
changing the rate limits without otherwise altering the function's behavior.
When a rate limited function has its rate limits updated, the previous rate
limits and any calls that would have counted against those rate limits are
immediately forgotten, and only the new rate limits are obeyed going forward.
# NOT RUN {f <- function() NULLf_lim <- limit_rate(f, rate(n = 1, period = .1))
# update the rate limits to 2 calls per .1 secondUPDATE_RATE(f_lim, rate(n = 2, period = .1))
# }