Addressed most feedback from reviews by refactoring:

- Made ResourceRequest a first class entity rather than a nested interface
- Refactored TimeoutConfig to tease apart an OpTimeMap which may be more generally useful.
- Renamed slow storage configs in Voldemort config with to make their testing nature more clear.
- Dropped OperationDelays object from SlowStorage in favor of OpTimeMap

src/java/voldemort/utils/OpTimeMap.java

@@ -0,0 +1,40 @@
+package voldemort.utils;
+
+import java.util.HashMap;
+
+import voldemort.common.VoldemortOpCode;
+
+/**
+ * Encapsulates time to operation mapping
+ * 
+ */
+public class OpTimeMap {
+
+    private HashMap<Byte, Long> timeMap;
+
+    public OpTimeMap(long time) {
+        this(time, time, time, time, time);
+    }
+
+    public OpTimeMap(long getTime,
+                     long putTime,
+                     long deleteTime,
+                     long getAllTime,
+                     long getVersionsTime) {
+        timeMap = new HashMap<Byte, Long>();
+        timeMap.put(VoldemortOpCode.GET_OP_CODE, getTime);
+        timeMap.put(VoldemortOpCode.PUT_OP_CODE, putTime);
+        timeMap.put(VoldemortOpCode.DELETE_OP_CODE, deleteTime);
+        timeMap.put(VoldemortOpCode.GET_ALL_OP_CODE, getAllTime);
+        timeMap.put(VoldemortOpCode.GET_VERSION_OP_CODE, getVersionsTime);
+    }
+
+    public long getOpTime(Byte opCode) {
+        assert timeMap.containsKey(opCode);
+        return timeMap.get(opCode);
+    }
+
+    public void setOpTime(Byte opCode, long time) {
+        timeMap.put(opCode, time);
+    }
+}

src/java/voldemort/utils/pool/ResourceRequest.java

@@ -0,0 +1,35 @@
+package voldemort.utils.pool;
+
+/**
+ * Interface for asynchronous requests for resources. Exactly one of
+ * useResource, handleTimeout, or handleException expected to be invoked within
+ * deadline specified by getDeadlineNs.
+ */
+public interface ResourceRequest<V> {
+
+    /**
+     * To be invoked with resource to use.
+     * 
+     * @param resource. resource should not be null.
+     */
+    void useResource(V resource);
+
+    /**
+     * Invoked sometime after deadline.
+     */
+    void handleTimeout();
+
+    /**
+     * Invoked upon exception trying to process resource request.
+     * 
+     * @param e
+     */
+    void handleException(Exception e);
+
+    /**
+     * 
+     * @return Deadline (in nanoseconds), after which handleTimeout() should be
+     *         invoked.
+     */
+    long getDeadlineNs();
+}