add 0 check

Author: Fred1155

core/sdk-core/src/main/java/software/amazon/awssdk/core/internal/http/pipeline/stages/AsyncApiCallAttemptMetricCollectionStage.java

@@ -123,6 +123,10 @@ private void reportWriteThroughput(RequestExecutionContext context) {
         long firstByteTime = metrics.firstByteWrittenNanoTime().get();
         if (bytesWritten > 0 && firstByteTime > 0) {
             long lastByteTime = metrics.lastByteWrittenNanoTime().get();
+            // Skip reporting if duration is zero
+            if (firstByteTime == lastByteTime) {
+                return;
+            }
             double writeThroughput = MetricUtils.bytesPerSec(bytesWritten, firstByteTime, lastByteTime);
             context.attemptMetricCollector().reportMetric(CoreMetric.WRITE_THROUGHPUT, writeThroughput);
         }

core/sdk-core/src/main/java/software/amazon/awssdk/core/internal/http/pipeline/stages/HandleResponseStage.java

@@ -85,6 +85,10 @@ private void reportWriteThroughput(RequestExecutionContext context, MetricCollec
         long firstByteTime = metrics.firstByteWrittenNanoTime().get();
         if (bytesWritten > 0 && firstByteTime > 0) {
             long lastByteTime = metrics.lastByteWrittenNanoTime().get();
+            // Skip reporting if duration is zero
+            if (firstByteTime == lastByteTime) {
+                return;
+            }
             double writeThroughput = MetricUtils.bytesPerSec(bytesWritten, firstByteTime, lastByteTime);
             attemptMetricCollector.reportMetric(CoreMetric.WRITE_THROUGHPUT, writeThroughput);
         }

core/sdk-core/src/main/java/software/amazon/awssdk/core/internal/util/MetricUtils.java

@@ -182,6 +182,9 @@ public static OptionalLong responseHeadersReadEndNanoTime(RequestExecutionContex
 
     public static double bytesPerSec(long totalBytes, long nanoStart, long nanoEnd) {
         long duration = nanoEnd - nanoStart;
+        if (duration <= 0) {
+            return 0.0; // for defensive programming. This won't be reached ideally
+        }
         double bytesPerNs = (double) totalBytes / duration;
         return bytesPerNs * ONE_SEC_IN_NS;
     }