diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index aee6f06..f95a898 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -107,7 +107,7 @@ jobs:
           command: tarpaulin
           args: --run-types Tests,Doctests --features full --workspace --out Xml
       - name: Upload to codecov.io
-        uses: codecov/codecov-action@v3.1.1
+        uses: codecov/codecov-action@v3.1.4
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           fail_ci_if_error: true
diff --git a/examples/async_example.rs b/examples/async_example.rs
index 7667032..f9d87b9 100644
--- a/examples/async_example.rs
+++ b/examples/async_example.rs
@@ -3,21 +3,30 @@ use stretto::AsyncCache;
 
 #[tokio::main]
 async fn main() {
-    let c: AsyncCache<&str, &str> = AsyncCache::new(12960, 1e6 as i64, tokio::spawn).unwrap();
+    // cache is intended to take ownership of key and value
+    let c: AsyncCache<String, String> = AsyncCache::new(12960, 1e6 as i64, tokio::spawn).unwrap();
 
     // set a value with a cost of 1
-    c.insert("a", "a", 1).await;
+    c.insert("key1".to_string(), "value1".to_string(), 1).await;
 
     // set a value with a cost of 1 and ttl
-    c.insert_with_ttl("b", "b", 1, Duration::from_secs(3)).await;
+    c.insert_with_ttl(
+        "key2".to_string(),
+        "value2".to_string(),
+        1,
+        Duration::from_secs(3),
+    )
+    .await;
 
     // wait for value to pass through buffers
     c.wait().await.unwrap();
 
+    // Create a search key
+    let key1 = "key1".to_string();
     // when we get the value, we will get a ValueRef, which contains a RwLockReadGuard
     // so when we finish use this value, we must release the ValueRef
-    let v = c.get(&"a").await.unwrap();
-    assert_eq!(v.value(), &"a");
+    let v = c.get(&key1).await.unwrap();
+    assert_eq!(v.value(), &"value1");
     // release the value
     v.release(); // or drop(v)
 
@@ -25,19 +34,18 @@ async fn main() {
     {
         // when we get the value, we will get a ValueRef, which contains a RwLockWriteGuard
         // so when we finish use this value, we must release the ValueRefMut
-        let mut v = c.get_mut(&"a").await.unwrap();
-        v.write("aa");
-        assert_eq!(v.value(), &"aa");
+        let mut v = c.get_mut(&key1).await.unwrap();
+        v.write("value2".to_string());
+        assert_eq!(v.value(), &"value2");
         // release the value
     }
 
     // if you just want to do one operation
-    let v = c.get_mut(&"a").await.unwrap();
-    v.write_once("aaa");
+    let v = c.get_mut(&key1).await.unwrap();
+    v.write_once("value3".to_string());
 
-    let v = c.get(&"a").await.unwrap();
-    println!("{}", v);
-    assert_eq!(v.value(), &"aaa");
+    let v = c.get(&key1).await.unwrap();
+    assert_eq!(v.value(), &"value3");
     v.release();
 
     // clear the cache
@@ -45,5 +53,5 @@ async fn main() {
     // wait all the operations are finished
     c.wait().await.unwrap();
 
-    assert!(c.get(&"a").await.is_none());
+    assert!(c.get(&key1).await.is_none());
 }
diff --git a/examples/sync_example.rs b/examples/sync_example.rs
index accf21e..59aa147 100644
--- a/examples/sync_example.rs
+++ b/examples/sync_example.rs
@@ -2,43 +2,51 @@ use std::time::Duration;
 use stretto::Cache;
 
 fn main() {
+    // cache is intended to take ownership of key and value
     let c = Cache::new(12960, 1e6 as i64).unwrap();
 
     // set a value with a cost of 1
-    c.insert("a", "a", 1);
+    c.insert("key1".to_string(), "value1".to_string(), 1);
     // set a value with a cost of 1 and ttl
-    c.insert_with_ttl("b", "b", 1, Duration::from_secs(3));
+    c.insert_with_ttl(
+        "key2".to_string(),
+        "value2".to_string(),
+        1,
+        Duration::from_secs(3),
+    );
 
     // wait for value to pass through buffers
     c.wait().unwrap();
 
+    // Create a search key
+    let key1 = "key1".to_string();
     // when we get the value, we will get a ValueRef, which contains a RwLockReadGuard
     // so when we finish use this value, we must release the ValueRef
-    let v = c.get(&"a").unwrap();
-    assert_eq!(v.value(), &"a");
+    let v = c.get(&key1).unwrap();
+    assert_eq!(v.value(), &"value1");
     v.release();
 
     // lock will be auto released when out of scope
     {
         // when we get the value, we will get a ValueRef, which contains a RwLockWriteGuard
         // so when we finish use this value, we must release the ValueRefMut
-        let mut v = c.get_mut(&"a").unwrap();
-        v.write("aa");
-        assert_eq!(v.value(), &"aa");
+        let mut v = c.get_mut(&key1).unwrap();
+        v.write("value3".to_string());
+        assert_eq!(v.value(), &"value3");
         // release the value
     }
 
     // if you just want to do one operation
-    let v = c.get_mut(&"a").unwrap();
-    v.write_once("aaa");
+    let v = c.get_mut(&key1).unwrap();
+    v.write_once("value4".to_string());
 
-    let v = c.get(&"a").unwrap();
-    assert_eq!(v.value(), &"aaa");
+    let v = c.get(&key1).unwrap();
+    assert_eq!(v.value(), &"value4");
     v.release();
 
     // clear the cache
     c.clear().unwrap();
     // wait all the operations are finished
     c.wait().unwrap();
-    assert!(c.get(&"a").is_none());
+    assert!(c.get(&key1).is_none());
 }
diff --git a/src/bbloom.rs b/src/bbloom.rs
index f80117a..57f95be 100644
--- a/src/bbloom.rs
+++ b/src/bbloom.rs
@@ -31,7 +31,8 @@ struct EntriesLocs {
     locs: u64,
 }
 
-fn calc_size_by_wrong_positives(num_entries: f64, wrongs: f64) -> EntriesLocs {
+fn calc_size_by_wrong_positives(num_entries: usize, wrongs: f64) -> EntriesLocs {
+    let num_entries = num_entries as f64;
     let size = -1f64 * num_entries * wrongs.ln() / LN_2.powf(2f64);
     let locs = (LN_2 * size / num_entries).ceil();
 
@@ -56,7 +57,7 @@ impl Bloom {
     pub fn new(cap: usize, false_positive_ratio: f64) -> Self {
         let entries_locs = {
             if false_positive_ratio < 1f64 {
-                calc_size_by_wrong_positives(cap as f64, false_positive_ratio)
+                calc_size_by_wrong_positives(cap, false_positive_ratio)
             } else {
                 EntriesLocs {
                     entries: cap as u64,
diff --git a/src/cache/builder.rs b/src/cache/builder.rs
index f171944..c79d218 100644
--- a/src/cache/builder.rs
+++ b/src/cache/builder.rs
@@ -140,23 +140,9 @@ where
     /// set num_counters to 100,000. The important thing is the *number of unique items* in the full cache,
     /// not necessarily the `max_cost` value.
     #[inline]
-    pub fn set_num_counters(self, num_counters: usize) -> Self {
-        Self {
-            num_counters,
-            max_cost: self.max_cost,
-            buffer_items: self.buffer_items,
-            insert_buffer_size: self.insert_buffer_size,
-            metrics: self.metrics,
-            callback: self.callback,
-            key_to_hash: self.key_to_hash,
-            update_validator: self.update_validator,
-            coster: self.coster,
-            ignore_internal_cost: self.ignore_internal_cost,
-            cleanup_duration: self.cleanup_duration,
-            marker_k: self.marker_k,
-            marker_v: self.marker_v,
-            hasher: self.hasher,
-        }
+    pub fn set_num_counters(mut self, num_counters: usize) -> Self {
+        self.num_counters = num_counters;
+        self
     }
 
     /// Set the max_cost for the Cache.
@@ -170,43 +156,15 @@ where
     ///
     /// `max_cost` could be anything as long as it matches how you're using the cost values when calling `insert`.
     #[inline]
-    pub fn set_max_cost(self, max_cost: i64) -> Self {
-        Self {
-            num_counters: self.num_counters,
-            max_cost,
-            buffer_items: self.buffer_items,
-            insert_buffer_size: self.insert_buffer_size,
-            metrics: self.metrics,
-            callback: self.callback,
-            key_to_hash: self.key_to_hash,
-            update_validator: self.update_validator,
-            coster: self.coster,
-            ignore_internal_cost: self.ignore_internal_cost,
-            cleanup_duration: self.cleanup_duration,
-            hasher: self.hasher,
-            marker_k: self.marker_k,
-            marker_v: self.marker_v,
-        }
+    pub fn set_max_cost(mut self, max_cost: i64) -> Self {
+        self.max_cost = max_cost;
+        self
     }
 
     #[inline]
-    pub fn set_buffer_items(self, sz: usize) -> Self {
-        Self {
-            num_counters: self.num_counters,
-            max_cost: self.max_cost,
-            buffer_items: sz,
-            insert_buffer_size: self.insert_buffer_size,
-            metrics: self.metrics,
-            callback: self.callback,
-            key_to_hash: self.key_to_hash,
-            update_validator: self.update_validator,
-            coster: self.coster,
-            ignore_internal_cost: self.ignore_internal_cost,
-            cleanup_duration: self.cleanup_duration,
-            hasher: self.hasher,
-            marker_k: self.marker_k,
-            marker_v: self.marker_v,
-        }
+    pub fn set_buffer_items(mut self, sz: usize) -> Self {
+        self.buffer_items = sz;
+        self
     }
 
     /// Set the insert buffer size for the Cache.
@@ -217,23 +175,9 @@ where
     /// try increasing this value in increments of 32 * 1024.
     /// This is a fine-tuning mechanism and you probably won't have to touch this.
     #[inline]
-    pub fn set_buffer_size(self, sz: usize) -> Self {
-        Self {
-            num_counters: self.num_counters,
-            max_cost: self.max_cost,
-            buffer_items: self.buffer_items,
-            insert_buffer_size: sz,
-            metrics: self.metrics,
-            callback: self.callback,
-            key_to_hash: self.key_to_hash,
-            update_validator: self.update_validator,
-            coster: self.coster,
-            ignore_internal_cost: self.ignore_internal_cost,
-            cleanup_duration: self.cleanup_duration,
-            hasher: self.hasher,
-            marker_k: self.marker_k,
-            marker_v: self.marker_v,
-        }
+    pub fn set_buffer_size(mut self, sz: usize) -> Self {
+            self.insert_buffer_size = sz;
+        self
     }
 
     /// Set whether record the metrics or not.
@@ -241,23 +185,9 @@ where
     /// Metrics is true when you want real-time logging of a variety of stats.
     /// The reason this is a CacheBuilderCore flag is because there's a 10% throughput performance overhead.
     #[inline]
-    pub fn set_metrics(self, val: bool) -> Self {
-        Self {
-            num_counters: self.num_counters,
-            max_cost: self.max_cost,
-            buffer_items: self.buffer_items,
-            insert_buffer_size: self.insert_buffer_size,
-            metrics: val,
-            callback: self.callback,
-            key_to_hash: self.key_to_hash,
-            update_validator: self.update_validator,
-            coster: self.coster,
-            ignore_internal_cost: self.ignore_internal_cost,
-            cleanup_duration: self.cleanup_duration,
-            hasher: self.hasher,
-            marker_k: self.marker_k,
-            marker_v: self.marker_v,
-        }
+    pub fn set_metrics(mut self, val: bool) -> Self {
+        self.metrics = val;
+        self
     }
 
     /// Set whether ignore the internal cost or not.
@@ -266,44 +196,16 @@ where
     /// because the size of stored item in Cache is 56(excluding the size of value).
     /// Set it to true to ignore the internal cost.
     #[inline]
-    pub fn set_ignore_internal_cost(self, val: bool) -> Self {
-        Self {
-            num_counters: self.num_counters,
-            max_cost: self.max_cost,
-            buffer_items: self.buffer_items,
-            insert_buffer_size: self.insert_buffer_size,
-            metrics: self.metrics,
-            callback: self.callback,
-            key_to_hash: self.key_to_hash,
-            update_validator: self.update_validator,
-            coster: self.coster,
-            ignore_internal_cost: val,
-            cleanup_duration: self.cleanup_duration,
-            hasher: self.hasher,
-            marker_k: self.marker_k,
-            marker_v: self.marker_v,
-        }
+    pub fn set_ignore_internal_cost(mut self, val: bool) -> Self {
+        self.ignore_internal_cost = val;
+        self
     }
 
     /// Set the cleanup ticker for Cache, each tick the Cache will clean the expired entries.
     #[inline]
-    pub fn set_cleanup_duration(self, d: Duration) -> Self {
-        Self {
-            num_counters: self.num_counters,
-            max_cost: self.max_cost,
-            buffer_items: self.buffer_items,
-            insert_buffer_size: self.insert_buffer_size,
-            metrics: self.metrics,
-            callback: self.callback,
-            key_to_hash: self.key_to_hash,
-            update_validator: self.update_validator,
-            coster: self.coster,
-            ignore_internal_cost: self.ignore_internal_cost,
-            cleanup_duration: d,
-            hasher: self.hasher,
-            marker_k: self.marker_k,
-            marker_v: self.marker_v,
-        }
+    pub fn set_cleanup_duration(mut self, d: Duration) -> Self {
+        self.cleanup_duration = d;
+        self
     }
 
     /// Set the [`KeyBuilder`] for the Cache