eagerly await activities in separate thread

engine-core/src/main/java/io/nosqlbench/engine/core/lifecycle/ActivityFinisher.java

@@ -0,0 +1,23 @@
+package io.nosqlbench.engine.core.lifecycle;
+
+public class ActivityFinisher extends Thread {
+
+    private final ActivityExecutor executor;
+    private final int timeout;
+    private boolean result;
+
+    public ActivityFinisher(ActivityExecutor executor, int timeout) {
+        super(executor.getActivityDef().getAlias() + "_finisher");
+        this.executor = executor;
+        this.timeout = timeout;
+    }
+
+    @Override
+    public void run() {
+        result = executor.awaitCompletion(timeout);
+    }
+
+    public boolean getResult() {
+        return result;
+    }
+}