fix all warnings

rust/src/main.rs

@@ -20,11 +20,7 @@ use log::{log, LogMessage};
 use once_cell::sync::Lazy;
 use plant_state::PlantState;
 use serde::{Deserialize, Serialize};
-use std::sync::MutexGuard;
-use std::{
-    fmt::Display,
-    sync::{atomic::AtomicBool, Arc, Mutex},
-};
+use std::sync::{atomic::AtomicBool, Arc, Mutex, MutexGuard};
 use tank::*;
 
 mod config;
@@ -841,15 +837,6 @@ fn main() {
     }
 }
 
-fn to_string<T: Display>(value: anyhow::Result<T>) -> String {
-    match value {
-        Ok(v) => v.to_string(),
-        Err(err) => {
-            format!("{:?}", err)
-        }
-    }
-}
-
 pub fn in_time_range(cur: &DateTime<Tz>, start: u8, end: u8) -> bool {
     let curhour = cur.hour() as u8;
     //eg 10-14