commit 8e1854ef6a5f0d392dac3355d659569b2564148b
Author: Alexis Midon <alexis.midon@airbnb.com>
Date:   Wed Aug 13 17:55:36 2014 -0700

    KAFKA-1594: adds the total number of queued responses as a metric

diff --git core/src/main/scala/kafka/network/RequestChannel.scala core/src/main/scala/kafka/network/RequestChannel.scala
index 60b0400..4560d8f 100644
--- core/src/main/scala/kafka/network/RequestChannel.scala
+++ core/src/main/scala/kafka/network/RequestChannel.scala
@@ -121,6 +121,10 @@ class RequestChannel(val numProcessors: Int, val queueSize: Int) extends KafkaMe
     }
   )
 
+  newGauge("ResponseQueueSize", new Gauge[Int]{
+    def value = responseQueues.foldLeft(0) {(total, q) => total + q.size()}
+  })
+
   for(i <- 0 until numProcessors) {
     newGauge(
       "Processor-" + i + "-ResponseQueueSize",