diff --git a/src/internal/mana_nng.hpp b/src/internal/mana_nng.hpp
index 32b0bb1..9d99630 100644
--- a/src/internal/mana_nng.hpp
+++ b/src/internal/mana_nng.hpp
@@ -13,7 +13,7 @@ struct MessageHeader
 {
     enum MessageType
     {
-        BeginRun,
+        BeginRun = 42,
         EndRun,
         EventData,
     };
@@ -25,7 +25,8 @@ struct MessageHeader
 // could transmit eventindex and array count as u16|u16 or sequence number and eventindex
 struct EventDataHeader
 {
-    u32 eventIndex;
+    u16 eventIndex;
+    u16 arrayCount;
     u32 sizeBytes;
 };
 
@@ -50,12 +51,12 @@ class NngServerSink: public IManaSink
     {
         auto len = std::strlen(descriptor_json);
         auto required = sizeof(MessageHeader) + len + 1;
-        auto msg = nng::allocate_message(required);
+        auto msg = nng::allocate_reserve_message(required);
         MessageHeader header{MessageHeader::BeginRun};
         nng_msg_append(msg.get(), &header, sizeof(header));
         nng_msg_append(msg.get(), descriptor_json, len + 1);
 
-        spdlog::info("Sending BeginRun message");
+        spdlog::info("Sending BeginRun message (size={})", nng_msg_len(msg.get()));
         int res = 0;
 
         do
@@ -83,19 +84,28 @@ class NngServerSink: public IManaSink
                 return;
             }
             else if (!res)
+            {
+                spdlog::info("begin_run: Received response from client");
                 break;
+            }
         }
     }
 
     void end_run(const char *descriptor_json) override
     {
+        if (msg_)
+        {
+            if (!flush())
+                return;
+        }
+
         auto len = std::strlen(descriptor_json);
         auto required = sizeof(MessageHeader) + len + 1;
-        auto msg = nng::allocate_message(required);
+        auto msg = nng::allocate_reserve_message(required);
         MessageHeader header{MessageHeader::EndRun};
         nng_msg_append(msg.get(), &header, sizeof(header));
         nng_msg_append(msg.get(), descriptor_json, len + 1);
-        spdlog::info("Sending EndRun message");
+        spdlog::info("Sending EndRun message (size={})", nng_msg_len(msg.get()));
         int res = 0;
 
         do
@@ -145,6 +155,7 @@ class NngServerSink: public IManaSink
 
         EventDataHeader header{};
         header.eventIndex = eventIndex;
+        header.arrayCount = arrayCount;
         header.sizeBytes = totalBytes;
         nng_msg_append(msg_.get(), &header, sizeof(header));
         nng_msg_append(msg_.get(), arrays, totalBytes);
@@ -162,7 +173,7 @@ class NngServerSink: public IManaSink
         if (!msg_)
             return false;
 
-        spdlog::info("Sending EventData message of size {}", nng_msg_len(msg_.get()));
+        spdlog::debug("Sending EventData message of size {}", nng_msg_len(msg_.get()));
 
         while (true)
         {
diff --git a/src/mana_plugin_nng_server.cc b/src/mana_plugin_nng_server.cc
index a50217a..1bab998 100644
--- a/src/mana_plugin_nng_server.cc
+++ b/src/mana_plugin_nng_server.cc
@@ -35,7 +35,7 @@ class Plugin: public IManaPlugin
 MANA_CPP_PLUGIN()
 {
     static Plugin *plugin;
-    static const char *listenUrl = "ipc://mana_nng_server.socket";
+    static const char *listenUrl = "ipc:///tmp/mana_nng_server.socket";
 
     if (plugin)
     {