public void insertOperation(final MemcachedNode node, final Operation o) {
    o.setHandlingNode(node);
    o.initialize();
    node.insertOp(o);
    addedQueue.offer(node);
    metrics.markMeter(OVERALL_REQUEST_METRIC);

    Selector s = selector.wakeup();
    assert s == selector : "Wakeup returned the wrong selector.";
    getLogger().debug("Added %s to %s", o, node);
  }
Insert an operation on the given node to the beginning of the queue.

@param node the node where to insert the {@link Operation}.
@param o the operation to insert.
src/main/java/net/spy/memcached/MemcachedConnection.java