diff --git a/clients/src/main/java/org/apache/kafka/clients/producer/internals/Sender.java b/clients/src/main/java/org/apache/kafka/clients/producer/internals/Sender.java
index e8c194c..34f474e 100644
--- a/clients/src/main/java/org/apache/kafka/clients/producer/internals/Sender.java
+++ b/clients/src/main/java/org/apache/kafka/clients/producer/internals/Sender.java
@@ -101,7 +101,9 @@ public class Sender implements Runnable {
             }
         }
 
-        // send anything left in the accumulator
+        // okay we stopped accepting requests but there may still be
+        // requests in the accumulator or waiting for acknowledgment,
+        // wait until these are completed.
         int unsent = 0;
         do {
             try {
@@ -109,7 +111,7 @@ public class Sender implements Runnable {
             } catch (Exception e) {
                 e.printStackTrace();
             }
-        } while (unsent > 0);
+        } while (unsent > 0 || this.inFlightRequests.totalInFlightRequests() > 0);
 
         // close all the connections
         this.selector.close();
@@ -518,6 +520,13 @@ public class Sender implements Runnable {
                 return requests.remove(node);
             }
         }
+
+        public int totalInFlightRequests() {
+            int total = 0;
+            for (Deque<InFlightRequest> deque : this.requests.values())
+                total += deque.size();
+            return total;
+        }
     }
 
 }
diff --git a/core/src/test/resources/log4j.properties b/core/src/test/resources/log4j.properties
index d7d03ea..df572f2 100644
--- a/core/src/test/resources/log4j.properties
+++ b/core/src/test/resources/log4j.properties
@@ -12,7 +12,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-log4j.rootLogger=OFF, stdout
+log4j.rootLogger=DEBUG, stdout
 
 log4j.appender.stdout=org.apache.log4j.ConsoleAppender
 log4j.appender.stdout.layout=org.apache.log4j.PatternLayout