GCRA: A basic implementation

Library which implements the core GCRA functionality in rust.

Usage

```rust use gcra::{GcraState, RateLimit};

fn checkratelimit() { const LIMIT: u32 = 1; // Create a rate limit that allows 1/1s let ratelimit = RateLimit::persec(LIMIT);

let mut userstate = GcraState::default(); assert!(userstate.checkandmodify(&ratelimit, 1).isok()); assert!( userstate.checkandmodify(&ratelimit, 1).is_err(), "We should be over the limit now" ); } ```