add ttfb to store client output (#308)

Adds Time-to-First-Byte (ttfb) to the store client output.

src/clients/cache/momento/http.rs

@@ -272,10 +272,7 @@ async fn task(
                     let start = Instant::now();
 
                     if let Ok((response, mut stream)) = sender.send_request(request, false) {
-                        if stream
-                            .send_data(Bytes::from(r.value.clone()), true)
-                            .is_err()
-                        {
+                        if stream.send_data(r.value.clone(), true).is_err() {
                             continue;
                         }
 

src/clients/store/s3/mod.rs

@@ -126,8 +126,7 @@ async fn task(
 
         let work_item = match work_receiver.recv().await {
             Ok(w) => w,
-            Err(e) => {
-                error!("error while attempting to receive work item: {e}");
+            Err(_) => {
                 continue;
             }
         };
@@ -440,7 +439,7 @@ impl S3RequestBuilder {
 
         self.inner
             .header("authorization", authorization)
-            .body(Full::<Bytes>::new(self.content.into()))
+            .body(Full::<Bytes>::new(self.content))
             .unwrap()
     }
 

src/output/mod.rs

@@ -257,6 +257,7 @@ fn store_stats(snapshot: &mut MetricsSnapshot) {
     let connect_sr = 100.0 * connect_ok / connect_total;
 
     let response_latency = snapshot.percentiles(STORE_RESPONSE_LATENCY_HISTOGRAM);
+    let response_ttfb = snapshot.percentiles(STORE_RESPONSE_TTFB_HISTOGRAM);
 
     output!(
         "Store Client Connection: Open: {} Success Rate: {:.2} %",
@@ -313,6 +314,15 @@ fn store_stats(snapshot: &mut MetricsSnapshot) {
     }
 
     output!("{latencies}");
+
+    let mut latencies = "Store Client Time-to-First-Byte (us):".to_owned();
+
+    for (label, _percentile, nanoseconds) in response_ttfb {
+        let microseconds = nanoseconds / 1000;
+        latencies.push_str(&format!(" {label}: {microseconds}"))
+    }
+
+    output!("{latencies}");
 }
 
 /// Outputs store stats