JVMCBC-1071: Don't allow negative values to be sent into the ValueRec…

…order.

In the rare case where nanoTime goes backwards, we need to make sure that this
case is captured since the internal histogram doesn't like being sent negative
values.

Change-Id: Ie9d73b23246d5549f760db36cae56faaa55b1c85
Reviewed-on: https://review.couchbase.org/c/couchbase-jvm-clients/+/171579
Tested-by: Build Bot <build@couchbase.com>
Reviewed-by: Graham Pople <graham.pople@couchbase.com>

core-io/src/main/java/com/couchbase/client/core/msg/RequestContext.java

@@ -213,7 +213,10 @@ public RequestContext logicallyComplete() {
     }
 
     if (!(environment().meter() instanceof NoopMeter)) {
-      core().responseMetric(request).recordValue(logicalRequestLatency());
+      long latency = logicalRequestLatency();
+      if (latency > 0) {
+        core().responseMetric(request).recordValue(latency);
+      }
     }
 
     return this;
@@ -243,10 +246,11 @@ public long logicallyCompletedAt() {
    * calls).
    */
   public long logicalRequestLatency() {
-    if (logicallyCompletedAt == 0) {
+    long createdAt = request.createdAt();
+    if (logicallyCompletedAt == 0 || logicallyCompletedAt <= createdAt) {
       return 0;
     }
-    return logicallyCompletedAt - request.createdAt();
+    return logicallyCompletedAt - createdAt;
   }
 
   @Stability.Internal