SL-20473 Add GenericStreamingMessage and dummy handler to suppress packet loss and log spam noise when visiting GLTF enabled regions.

indra/newview/llstartup.cpp

@@ -3665,6 +3665,7 @@ void register_viewer_callbacks(LLMessageSystem* msg)
 	msg->setHandlerFunc("InitiateDownload", process_initiate_download);
 	msg->setHandlerFunc("LandStatReply", LLFloaterTopObjects::handle_land_reply);
     msg->setHandlerFunc("GenericMessage", process_generic_message);
+    msg->setHandlerFunc("GenericStreamingMessage", process_generic_streaming_message);
     msg->setHandlerFunc("LargeGenericMessage", process_large_generic_message);
 
 	msg->setHandlerFuncFast(_PREHASH_FeatureDisabled, process_feature_disabled_message);

indra/newview/llviewergenericmessage.cpp

@@ -92,6 +92,11 @@ void process_generic_message(LLMessageSystem* msg, void**)
 	}
 }
 
+void process_generic_streaming_message(LLMessageSystem* msg, void**)
+{
+    // placeholder to suppress packet loss reports and log spam (SL-20473)
+}
+
 void process_large_generic_message(LLMessageSystem* msg, void**)
 {
     LLUUID agent_id;

indra/newview/llviewergenericmessage.h

@@ -38,6 +38,7 @@ void send_generic_message(const std::string& method,
 						  const LLUUID& invoice = LLUUID::null);
 
 void process_generic_message(LLMessageSystem* msg, void**);
+void process_generic_streaming_message(LLMessageSystem* msg, void**);
 void process_large_generic_message(LLMessageSystem* msg, void**);
 
 

scripts/messages/message_template.msg

@@ -5807,6 +5807,25 @@ version 2.0
 	}
 }
 
+// GenericStreamingMessage
+// Optimized generic message for streaming arbitrary data to viewer
+// Avoid payloads over 7KB (8KB ceiling)
+// Method -- magic number indicating method to use to decode payload:
+//      0x4175 - GLTF material override data
+// Payload -- data to be decoded
+{
+    GenericStreamingMessage High 31 Trusted Unencoded
+    {
+        MethodData Single
+        { Method    U16 }
+    }
+
+    {
+        DataBlock Single
+        { Data Variable 2 }
+    }
+}
+
 // LargeGenericMessage
 // Similar to the above messages, but can handle larger payloads and serialized 
 // LLSD.  Uses HTTP transport 

scripts/messages/message_template.msg.sha1

@@ -1 +1 @@
-e61fad776b4d494be0b901922fc75a3317af97ca
+9eb8c673c2f6b4e271d50f07823757f98f406f0a