(cobra client and bots) add batch_size subscription option for retrieving multiple messages at once

test/IXCobraChatTest.cpp

@@ -125,10 +125,12 @@ namespace
     {
         std::string filter;
         std::string position("$");
+        int batchSize = 1;
 
         _conn.subscribe(channel,
                         filter,
                         position,
+                        batchSize,
                         [this](const Json::Value& msg, const std::string& /*position*/) {
                             spdlog::info("receive {}", msg.toStyledString());
 

test/IXCobraMetricsPublisherTest.cpp

@@ -76,10 +76,12 @@ namespace
                 log("Subscriber authenticated");
                 std::string filter;
                 std::string position("$");
+                int batchSize = 1;
 
                 conn.subscribe(channel,
                                filter,
                                position,
+                               batchSize,
                                [](const Json::Value& msg, const std::string& /*position*/) {
                                    log(msg.toStyledString());