In lqosd, replace lazy_static with once_cell, per Rust best practices

These days the Rust team are recommending "once_cell", which has
simpler syntax and does the same thing.

src/rust/Cargo.lock

@@ -1436,7 +1436,6 @@ dependencies = [
  "anyhow",
  "env_logger",
  "jemallocator",
- "lazy_static",
  "log",
  "lqos_bus",
  "lqos_config",
@@ -1444,6 +1443,7 @@ dependencies = [
  "lqos_sys",
  "lqos_utils",
  "nix",
+ "once_cell",
  "parking_lot",
  "rayon",
  "serde",

src/rust/lqosd/Cargo.toml

@@ -14,7 +14,7 @@ lqos_sys = { path = "../lqos_sys" }
 lqos_queue_tracker = { path = "../lqos_queue_tracker" }
 lqos_utils = { path = "../lqos_utils" }
 tokio = { version = "1", features = [ "full", "parking_lot" ] }
-lazy_static = "1.4"
+once_cell = "1.17.1"
 parking_lot = "0.12"
 lqos_bus = { path = "../lqos_bus" }
 signal-hook = "0.3"

src/rust/lqosd/src/throughput_tracker/mod.rs

@@ -1,20 +1,17 @@
 mod throughput_entry;
 mod tracking_data;
 use crate::throughput_tracker::tracking_data::ThroughputTracker;
-use lazy_static::*;
 use log::{info, warn};
 use lqos_bus::{BusResponse, IpStats, TcHandle, XdpPpingResult};
 use lqos_sys::XdpIpAddress;
 use lqos_utils::{fdtimer::periodic, unix_time::time_since_boot};
+use once_cell::sync::Lazy;
 use parking_lot::RwLock;
 use std::time::Duration;
 
 const RETIRE_AFTER_SECONDS: u64 = 30;
 
-lazy_static! {
+static THROUGHPUT_TRACKER: Lazy<RwLock<ThroughputTracker>> = Lazy::new(|| RwLock::new(ThroughputTracker::new()));
-  static ref THROUGHPUT_TRACKER: RwLock<ThroughputTracker> =
-    RwLock::new(ThroughputTracker::new());
-}
 
 pub fn spawn_throughput_monitor() {
   info!("Starting the bandwidth monitor thread.");