diff --git a/compiler/cpp/src/generate/t_cpp_generator.cc b/compiler/cpp/src/generate/t_cpp_generator.cc
index 8770ade..5056d87 100644
--- a/compiler/cpp/src/generate/t_cpp_generator.cc
+++ b/compiler/cpp/src/generate/t_cpp_generator.cc
@@ -2437,6 +2437,10 @@
         out <<
           indent() << "::apache::thrift::async::TConcurrentSendSentry sentry(&this->sync_);" << endl;
       }
+      if (style == "Cob") {
+        out <<
+          indent() << _this << "otrans_->resetBuffer();" << endl;
+      }
       out <<
         indent() << _this << "oprot_->writeMessageBegin(\"" << 
         (*f_iter)->get_name() << 
diff --git a/lib/cpp/src/thrift/async/TEvhttpClientChannel.cpp b/lib/cpp/src/thrift/async/TEvhttpClientChannel.cpp
index 1279bc6..74acfaa 100644
--- a/lib/cpp/src/thrift/async/TEvhttpClientChannel.cpp
+++ b/lib/cpp/src/thrift/async/TEvhttpClientChannel.cpp
@@ -39,7 +39,7 @@
                                            const char* address,
                                            int port,
                                            struct event_base* eb)
-  : host_(host), path_(path), recvBuf_(NULL), conn_(NULL) {
+  : host_(host), path_(path), conn_(NULL) {
   conn_ = evhttp_connection_new(address, port);
   if (conn_ == NULL) {
     throw TException("evhttp_connection_new failed");
@@ -56,9 +56,6 @@
 void TEvhttpClientChannel::sendAndRecvMessage(const VoidCallback& cob,
                                               apache::thrift::transport::TMemoryBuffer* sendBuf,
                                               apache::thrift::transport::TMemoryBuffer* recvBuf) {
-  cob_ = cob;
-  recvBuf_ = recvBuf;
-
   struct evhttp_request* req = evhttp_request_new(response, this);
   if (req == NULL) {
     throw TException("evhttp_request_new failed");
@@ -88,6 +85,8 @@
   if (rv != 0) {
     throw TException("evhttp_make_request failed");
   }
+
+  completionQueue_.push(Completion(cob, recvBuf));
 }
 
 void TEvhttpClientChannel::sendMessage(const VoidCallback& cob,
@@ -107,9 +106,12 @@
 }
 
 void TEvhttpClientChannel::finish(struct evhttp_request* req) {
+  assert(!completionQueue_.empty());
+  Completion completion = completionQueue_.front();
+  completionQueue_.pop();
   if (req == NULL) {
     try {
-      cob_();
+      completion.first();
     } catch (const TTransportException& e) {
       if (e.getType() == TTransportException::END_OF_FILE)
         throw TException("connect failed");
@@ -119,7 +121,7 @@
     return;
   } else if (req->response_code != 200) {
     try {
-      cob_();
+      completion.first();
     } catch (const TTransportException& e) {
       std::stringstream ss;
       ss << "server returned code " << req->response_code;
@@ -132,9 +134,9 @@
     }
     return;
   }
-  recvBuf_->resetBuffer(EVBUFFER_DATA(req->input_buffer),
+  completion.second->resetBuffer(EVBUFFER_DATA(req->input_buffer),
                         static_cast<uint32_t>(EVBUFFER_LENGTH(req->input_buffer)));
-  cob_();
+  completion.first();
   return;
 }
 
diff --git a/lib/cpp/src/thrift/async/TEvhttpClientChannel.h b/lib/cpp/src/thrift/async/TEvhttpClientChannel.h
index 72ed40f..72eb32d 100644
--- a/lib/cpp/src/thrift/async/TEvhttpClientChannel.h
+++ b/lib/cpp/src/thrift/async/TEvhttpClientChannel.h
@@ -20,7 +20,9 @@
 #ifndef _THRIFT_TEVHTTP_CLIENT_CHANNEL_H_
 #define _THRIFT_TEVHTTP_CLIENT_CHANNEL_H_ 1
 
+#include <queue>
 #include <string>
+#include <utility>
 #include <boost/shared_ptr.hpp>
 #include <thrift/async/TAsyncChannel.h>
 
@@ -72,8 +74,9 @@
 
   std::string host_;
   std::string path_;
-  VoidCallback cob_;
-  apache::thrift::transport::TMemoryBuffer* recvBuf_;
+  typedef std::pair<VoidCallback, apache::thrift::transport::TMemoryBuffer*> Completion;
+  typedef std::queue<Completion> CompletionQueue;
+  CompletionQueue completionQueue_;
   struct evhttp_connection* conn_;
 };
 }
diff --git a/test/cpp/src/TestClient.cpp b/test/cpp/src/TestClient.cpp
index 5d06c56..6aebcdc 100644
--- a/test/cpp/src/TestClient.cpp
+++ b/test/cpp/src/TestClient.cpp
@@ -23,6 +23,7 @@
 #include <locale>
 #include <ios>
 #include <iostream>
+#include <sstream>
 #include <thrift/protocol/TBinaryProtocol.h>
 #include <thrift/protocol/TCompactProtocol.h>
 #include <thrift/protocol/THeaderProtocol.h>
@@ -65,45 +66,38 @@
   return ret;
 }
 
-static void testString_clientReturn(const char* host,
-                                    int port,
-                                    event_base* base,
-                                    TProtocolFactory* protocolFactory,
+static void testString_clientReturn(event_base* base,
+                                    int testNr,
                                     ThriftTestCobClient* client) {
-  (void)host;
-  (void)port;
-  (void)protocolFactory;
   try {
     string s;
     client->recv_testString(s);
-    cout << "testString: " << s << endl;
+    std::ostringstream os;
+    os << "test" << testNr;
+    const bool ok = (s == os.str());
+    cout << "testString: " << s << " " << ((ok) ? "ok" : "failed") << endl;
   } catch (TException& exn) {
     cout << "Error: " << exn.what() << endl;
   }
 
-  event_base_loopbreak(base); // end test
+  if (testNr == 9)
+    event_base_loopbreak(base); // end test
 }
 
-static void testVoid_clientReturn(const char* host,
-                                  int port,
-                                  event_base* base,
-                                  TProtocolFactory* protocolFactory,
-                                  ThriftTestCobClient* client) {
+static void testVoid_clientReturn(event_base* base, ThriftTestCobClient* client) {
   try {
     client->recv_testVoid();
     cout << "testVoid" << endl;
 
-    // next test
-    delete client;
-    boost::shared_ptr<TAsyncChannel> channel(new TEvhttpClientChannel(host, "/", host, port, base));
-    client = new ThriftTestCobClient(channel, protocolFactory);
-    client->testString(tcxx::bind(testString_clientReturn,
-                                  host,
-                                  port,
-                                  base,
-                                  protocolFactory,
-                                  tcxx::placeholders::_1),
-                       "Test");
+    for (int testNr = 0; testNr < 10; ++testNr) {
+      std::ostringstream os;
+      os << "test" << testNr;
+      client->testString(tcxx::bind(testString_clientReturn,
+                                    base,
+                                    testNr,
+                                    tcxx::placeholders::_1),
+                       os.str());
+    }
   } catch (TException& exn) {
     cout << "Error: " << exn.what() << endl;
   }
@@ -306,10 +300,7 @@
         new TEvhttpClientChannel(host.c_str(), "/", host.c_str(), port, base));
     ThriftTestCobClient* client = new ThriftTestCobClient(channel, protocolFactory.get());
     client->testVoid(tcxx::bind(testVoid_clientReturn,
-                                host.c_str(),
-                                port,
                                 base,
-                                protocolFactory.get(),
                                 tcxx::placeholders::_1));
 
     event_base_loop(base, 0);