diff --git a/examples/lib.rs b/examples/lib.rs
index 3ca7463..ecc079f 100644
--- a/examples/lib.rs
+++ b/examples/lib.rs
@@ -8,11 +8,11 @@ pub async fn run_example(sched: &mut JobScheduler) -> Result<Vec<Uuid>, JobSched
     #[cfg(feature = "signal")]
     sched.shutdown_on_ctrl_c();
 
-    sched.set_shutdown_handler(Box::new(|| {
-        Box::pin(async move {
+    sched
+        .set_shutdown_handler(async move {
             info!("Shut down done");
         })
-    }));
+        .await;
 
     let mut five_s_job = Job::new("1/5 * * * * *", |uuid, _l| {
         info!(
@@ -27,7 +27,7 @@ pub async fn run_example(sched: &mut JobScheduler) -> Result<Vec<Uuid>, JobSched
     // the job store, but with stopped marking
     five_s_job
         .on_removed_notification_add(
-            &sched,
+            sched,
             Box::new(|job_id, notification_id, type_of_notification| {
                 Box::pin(async move {
                     info!(
@@ -55,7 +55,7 @@ pub async fn run_example(sched: &mut JobScheduler) -> Result<Vec<Uuid>, JobSched
     let four_s_job_async_clone = four_s_job_async.clone();
     let js = sched.clone();
     info!("4s job id {:?}", four_s_job_async.guid());
-    four_s_job_async.on_start_notification_add(&sched, Box::new(move |job_id, notification_id, type_of_notification| {
+    four_s_job_async.on_start_notification_add(sched, Box::new(move |job_id, notification_id, type_of_notification| {
         let four_s_job_async_clone = four_s_job_async_clone.clone();
         let js = js.clone();
         Box::pin(async move {
@@ -67,7 +67,7 @@ pub async fn run_example(sched: &mut JobScheduler) -> Result<Vec<Uuid>, JobSched
 
     four_s_job_async
         .on_done_notification_add(
-            &sched,
+            sched,
             Box::new(|job_id, notification_id, type_of_notification| {
                 Box::pin(async move {
                     info!(
diff --git a/examples/repeated_with_start_at.rs b/examples/repeated_with_start_at.rs
index 8e64fe1..ef2f39c 100644
--- a/examples/repeated_with_start_at.rs
+++ b/examples/repeated_with_start_at.rs
@@ -4,7 +4,7 @@ use tokio_cron_scheduler::{JobBuilder, JobScheduler};
 
 #[tokio::main]
 async fn main() {
-    println!("start at: {}", Local::now().to_rfc3339().to_string());
+    println!("start at: {:?}", Local::now().to_rfc3339());
 
     // 创建 scheduler
     let mut sched = JobScheduler::new().await.unwrap();
@@ -26,11 +26,11 @@ async fn main() {
         .start_at(datetime)
         // TODO：设置 job 的任务重叠策略
         // 设置 job 的异步执行函数
-        .with_run_async(Box::new(|uuid, mut l| {
+        .with_run_async(Box::new(|_uuid, mut _l| {
             Box::pin(async move {
-                println!(">>> {}", Local::now().to_rfc3339().to_string());
+                println!(">>> {:?}", Local::now().to_rfc3339());
                 tokio::time::sleep(Duration::from_secs(INTERVAL + 2)).await;
-                println!("<<< {}", Local::now().to_rfc3339().to_string());
+                println!("<<< {:?}", Local::now().to_rfc3339());
             })
         }))
         .build()
@@ -49,5 +49,5 @@ async fn main() {
 
     // 停止 scheduler
     sched.shutdown().await.unwrap();
-    println!("stop at: {}", Local::now().to_rfc3339().to_string());
+    println!("stop at: {:?}", Local::now().to_rfc3339());
 }
diff --git a/src/job/builder.rs b/src/job/builder.rs
index 15e667e..ea06b50 100644
--- a/src/job/builder.rs
+++ b/src/job/builder.rs
@@ -50,6 +50,12 @@ impl JobBuilder<Utc> {
     }
 }
 
+impl Default for JobBuilder<Utc> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl<T: TimeZone> JobBuilder<T> {
     pub fn with_timezone<U: TimeZone>(self, timezone: U) -> JobBuilder<U> {
         JobBuilder {
diff --git a/src/job/mod.rs b/src/job/mod.rs
index c0c9719..2e7c22a 100644
--- a/src/job/mod.rs
+++ b/src/job/mod.rs
@@ -60,6 +60,7 @@ fn nop_async(_uuid: Uuid, _jobs: JobsSchedulerLocked) -> Pin<Box<dyn Future<Outp
 pub struct JobLocked(pub(crate) Arc<RwLock<Box<dyn Job + Send + Sync>>>);
 
 pub trait Job {
+    #[allow(dead_code)]
     fn is_cron_job(&self) -> bool;
     fn schedule(&self) -> Option<Cron>;
     fn repeated_every(&self) -> Option<u64>;
@@ -69,17 +70,20 @@ pub trait Job {
     fn set_next_tick(&mut self, tick: Option<DateTime<Utc>>);
     fn set_count(&mut self, count: u32);
     fn count(&self) -> u32;
+    #[allow(dead_code)]
     fn increment_count(&mut self);
     fn job_id(&self) -> Uuid;
     fn job_type(&self) -> JobType;
     fn ran(&self) -> bool;
     fn set_ran(&mut self, ran: bool);
+    #[allow(dead_code)]
     fn stop(&self) -> bool;
     fn set_stopped(&mut self);
     fn set_started(&mut self);
     fn job_data_from_job(&mut self) -> Result<Option<JobStoredData>, JobSchedulerError>;
     fn set_job_data(&mut self, job_data: JobStoredData) -> Result<(), JobSchedulerError>;
     fn run(&mut self, jobs: JobScheduler) -> Receiver<bool>;
+    #[allow(dead_code)]
     fn fixed_offset_west(&self) -> i32;
 }
 
diff --git a/src/job_scheduler.rs b/src/job_scheduler.rs
index cfd7e31..ead3c96 100644
--- a/src/job_scheduler.rs
+++ b/src/job_scheduler.rs
@@ -8,7 +8,7 @@ use crate::simple::{
     SimpleJobCode, SimpleMetadataStore, SimpleNotificationCode, SimpleNotificationStore,
 };
 use crate::store::{MetaDataStorage, NotificationStore};
-use chrono::{DateTime, NaiveDateTime, Utc};
+use chrono::{DateTime, Utc};
 use std::future::Future;
 use std::pin::Pin;
 use std::sync::atomic::{AtomicBool, Ordering};
@@ -331,15 +331,12 @@ impl JobsSchedulerLocked {
 
         let mut metadata = self.context.metadata_storage.write().await;
         let jm = metadata.get(job_id).await?;
-        match jm {
-            Some(mut job_metadata) => {
-                job_metadata
-                    .last_updated
-                    .replace(Utc::now().timestamp() as u64);
-                job_metadata.ran = ran;
-                metadata.add_or_update(job_metadata).await?;
-            }
-            _ => {}
+        if let Some(mut job_metadata) = jm {
+            job_metadata
+                .last_updated
+                .replace(Utc::now().timestamp() as u64);
+            job_metadata.ran = ran;
+            metadata.add_or_update(job_metadata).await?;
         }
         Ok(())
     }
@@ -410,10 +407,7 @@ impl JobsSchedulerLocked {
                 if vv.next_tick == 0 {
                     return None;
                 }
-                match NaiveDateTime::from_timestamp_opt(vv.next_tick as i64, 0) {
-                    None => None,
-                    Some(ts) => Some(DateTime::from_naive_utc_and_offset(ts, Utc)),
-                }
+                DateTime::from_timestamp(vv.next_tick as i64, 0)
             } else {
                 None
             }
diff --git a/src/scheduler.rs b/src/scheduler.rs
index f1664ae..f564a60 100644
--- a/src/scheduler.rs
+++ b/src/scheduler.rs
@@ -75,10 +75,7 @@ impl Scheduler {
                 }
             }
             'next_tick: loop {
-                let shutdown = {
-                    let r = shutdown.load(Ordering::Relaxed);
-                    r
-                };
+                let shutdown = { shutdown.load(Ordering::Relaxed) };
                 if shutdown {
                     break 'next_tick;
                 }
diff --git a/src/store/metadata_store.rs b/src/store/metadata_store.rs
index c6ab02d..f8bac13 100644
--- a/src/store/metadata_store.rs
+++ b/src/store/metadata_store.rs
@@ -25,4 +25,5 @@ pub trait MetaDataStorage: DataStore<JobStoredData> + InitStore {
     ) -> Pin<Box<dyn Future<Output = Result<Option<std::time::Duration>, JobSchedulerError>> + Send>>;
 }
 
+#[allow(dead_code)]
 pub trait JobCodeGet: CodeGet<Box<JobToRunAsync>> {}
diff --git a/src/store/mod.rs b/src/store/mod.rs
index 859feee..738f244 100644
--- a/src/store/mod.rs
+++ b/src/store/mod.rs
@@ -33,6 +33,7 @@ where
     ) -> Pin<Box<dyn Future<Output = Result<(), JobSchedulerError>> + Send>>;
 }
 
+#[allow(dead_code)]
 pub trait CodeGet<CODE>
 where
     CODE: Sized,
diff --git a/src/store/notification_store.rs b/src/store/notification_store.rs
index 8a4e6b0..720508a 100644
--- a/src/store/notification_store.rs
+++ b/src/store/notification_store.rs
@@ -33,4 +33,5 @@ pub trait NotificationStore: DataStore<NotificationData> + InitStore {
     ) -> Pin<Box<dyn Future<Output = Result<(), JobSchedulerError>> + Send>>;
 }
 
+#[allow(dead_code)]
 pub trait NotificationRunnableCodeGet: CodeGet<Box<OnJobNotification>> {}