Sampling poisson distribution

src/utils/mod.rs

@@ -1 +1,2 @@
 pub mod bytes;
+pub mod poisson;

src/utils/poisson.rs

@@ -0,0 +1,6 @@
+use rand_distr::{Distribution, Exp};
+
+pub fn sample(average_delay: f64) -> f64 {
+    let exp = Exp::new(1.0 / average_delay).unwrap();
+    exp.sample(&mut rand::thread_rng())
+}