add customizable timers to CQL driver

engine-api/src/main/java/io/nosqlbench/engine/api/metrics/ThreadLocalNamedTimers.java

@@ -0,0 +1,53 @@
+package io.nosqlbench.engine.api.metrics;
+
+import com.codahale.metrics.Timer;
+import io.nosqlbench.engine.api.activityimpl.ActivityDef;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Auxiliary thread-local metrics for an activity which are tracked by name.
+ */
+public class ThreadLocalNamedTimers {
+
+    private final static Logger logger = LogManager.getLogger(ThreadLocalNamedTimers.class);
+
+    public final static ThreadLocal<ThreadLocalNamedTimers> TL_INSTANCE = ThreadLocal.withInitial(ThreadLocalNamedTimers::new);
+    private final static Map<String, Timer> timers = new HashMap<>();
+    private final Map<String, Timer.Context> contexts = new HashMap<>();
+
+    public static void addTimer(ActivityDef def, String name) {
+        if (timers.containsKey("name")) {
+            logger.warn("A timer named '" + name + "' was already defined and initialized.");
+        }
+        Timer timer = ActivityMetrics.timer(def, name);
+        timers.put(name, timer);
+    }
+
+    public void start(String name) {
+        Timer.Context context = timers.get(name).time();
+        contexts.put(name, context);
+    }
+
+    public void stop(String name) {
+        Timer.Context context = contexts.get(name);
+        context.stop();
+    }
+
+    public void start(List<String> timerName) {
+        for (String startTimer : timerName) {
+            start(startTimer);
+        }
+    }
+
+    public void stop(List<String> timerName) {
+        for (String stopTimer : timerName) {
+            stop(stopTimer);
+        }
+    }
+
+}