diff --git a/crates/datadog-serverless-compat/src/main.rs b/crates/datadog-serverless-compat/src/main.rs
index f763627..a13e753 100644
--- a/crates/datadog-serverless-compat/src/main.rs
+++ b/crates/datadog-serverless-compat/src/main.rs
@@ -143,7 +143,7 @@ pub async fn main() {
         }
     });
 
-    let (mut metrics_flusher, _aggregator_handle) = if dd_use_dogstatsd {
+    let (metrics_flusher, _aggregator_handle) = if dd_use_dogstatsd {
         debug!("Starting dogstatsd");
         let (_, metrics_flusher, aggregator_handle) = start_dogstatsd(
             dd_dogstatsd_port,
@@ -167,7 +167,7 @@ pub async fn main() {
     loop {
         flush_interval.tick().await;
 
-        if let Some(metrics_flusher) = metrics_flusher.as_mut() {
+        if let Some(metrics_flusher) = metrics_flusher.as_ref() {
             debug!("Flushing dogstatsd metrics");
             metrics_flusher.flush().await;
         }
diff --git a/crates/dogstatsd/src/flusher.rs b/crates/dogstatsd/src/flusher.rs
index 0de79c1..e4fbe4b 100644
--- a/crates/dogstatsd/src/flusher.rs
+++ b/crates/dogstatsd/src/flusher.rs
@@ -51,7 +51,7 @@ impl Flusher {
         }
     }
 
-    async fn get_dd_api(&mut self) -> &Option<DdApi> {
+    async fn get_dd_api(&self) -> &Option<DdApi> {
         self.dd_api
             .get_or_init(|| async {
                 let api_key = self.api_key_factory.get_api_key().await;
@@ -76,7 +76,7 @@ impl Flusher {
 
     /// Flush metrics from the aggregator
     pub async fn flush(
-        &mut self,
+        &self,
     ) -> Option<(
         Vec<crate::datadog::Series>,
         Vec<datadog_protos::metrics::SketchPayload>,
@@ -96,7 +96,7 @@ impl Flusher {
 
     /// Flush given batch of metrics
     pub async fn flush_metrics(
-        &mut self,
+        &self,
         series: Vec<crate::datadog::Series>,
         distributions: Vec<datadog_protos::metrics::SketchPayload>,
     ) -> Option<(
@@ -272,7 +272,7 @@ mod tests {
             None,
         );
 
-        let mut flusher = Flusher::new(FlusherConfig {
+        let flusher = Flusher::new(FlusherConfig {
             api_key_factory: Arc::new(api_key_factory),
             aggregator_handle: handle,
             metrics_intake_url_prefix: MetricsIntakeUrlPrefix::new(
@@ -319,7 +319,7 @@ mod tests {
 
         let api_key_factory = ApiKeyFactory::new("test-api-key");
 
-        let mut flusher = Flusher::new(FlusherConfig {
+        let flusher = Flusher::new(FlusherConfig {
             api_key_factory: Arc::new(api_key_factory),
             aggregator_handle: handle,
             metrics_intake_url_prefix: MetricsIntakeUrlPrefix::new(
@@ -369,7 +369,7 @@ mod tests {
 
         let api_key_factory = ApiKeyFactory::new("test-api-key");
 
-        let mut flusher = Flusher::new(FlusherConfig {
+        let flusher = Flusher::new(FlusherConfig {
             api_key_factory: Arc::new(api_key_factory),
             aggregator_handle: handle,
             metrics_intake_url_prefix: MetricsIntakeUrlPrefix::new(
diff --git a/crates/dogstatsd/tests/integration_test.rs b/crates/dogstatsd/tests/integration_test.rs
index 65d919c..9824a63 100644
--- a/crates/dogstatsd/tests/integration_test.rs
+++ b/crates/dogstatsd/tests/integration_test.rs
@@ -47,7 +47,7 @@ async fn dogstatsd_server_ships_series() {
 
     let api_key_factory = ApiKeyFactory::new("mock-api-key");
 
-    let mut metrics_flusher = Flusher::new(FlusherConfig {
+    let metrics_flusher = Flusher::new(FlusherConfig {
         api_key_factory: Arc::new(api_key_factory),
         aggregator_handle: handle.clone(),
         metrics_intake_url_prefix: MetricsIntakeUrlPrefix::new(