Crate mysteriouspants_throttle

A simple throttle, used for slowing down repeated code. Use this to avoid drowning out downstream systems. For example, if I were reading the contents of a file repeatedly (polling for data, perhaps), or calling an external network resource, I could use a Throttle to slow that down to avoid resource contention or browning out a downstream service. Another potential use of a Throttle is in video game code to lock a framerate lower to promote predictable gameplay or to avoid burning up user's graphics hardware unnecessarily.

This ranges in utility from a simple TPS throttle, "never go faster than x transactions per second,"

// create a new Throttle that rate limits to 10 TPS
let mut throttle = Throttle::new_tps_throttle(10.0);

let iteration_start = Instant::now();

// iterate eleven times, which at 10 TPS should take just over 1 second
for _i in 0..11 {
  throttle.acquire(());
  // do the needful
}

// prove that it did, in fact, take 1 second
assert_eq!(iteration_start.elapsed().as_secs() == 1, true);

To more complicated variable-rate throttles, which may be as advanced as to slow in response to backpressure.

let mut throttle = Throttle::new_variable_throttle(
    |arg: u64, _| Duration::from_millis(arg));

let iteration_start = Instant::now();

for i in 0..5 {
  throttle.acquire(i * 100);
}

assert_eq!(iteration_start.elapsed().as_secs() == 1, true);

When using your throttle, keep in mind that you are responsible for sharing it between threads safely and responsibly.

Structs

Throttle

A simple configurable throttle for slowing down code, a little struct holding some state.