LwM2M improved tracking of sent requests

common/transport/lwm2m/src/main/java/org/thingsboard/server/transport/lwm2m/server/downlink/DefaultLwM2mDownlinkMsgHandler.java

@@ -319,7 +319,8 @@ public class DefaultLwM2mDownlinkMsgHandler extends LwM2MExecutorAwareService im
                         clientContext.awake(client);
                     }
                 });
-            },e -> handleDownlinkError(client, request, callback, e));
+            }, e -> handleDownlinkError(client, request, callback, e));
+            callback.onSent(request);
         } catch (Exception e) {
             handleDownlinkError(client, request, callback, e);
         }

common/transport/lwm2m/src/main/java/org/thingsboard/server/transport/lwm2m/server/downlink/DownlinkRequestCallback.java

@@ -17,29 +17,12 @@ package org.thingsboard.server.transport.lwm2m.server.downlink;
 
 public interface DownlinkRequestCallback<R, T> {
 
+    default void onSent(R request){};
+
     void onSuccess(R request, T response);
 
     void onValidationError(String params, String msg);
 
     void onError(String params, Exception e);
 
-    static <R, T> DownlinkRequestCallback<R, T> doNothing() {
-        return new DownlinkRequestCallback<>() {
-
-            @Override
-            public void onSuccess(R request, T response) {
-
-            }
-
-            @Override
-            public void onValidationError(String params, String msg) {
-
-            }
-
-            @Override
-            public void onError(String params, Exception e) {
-
-            }
-        };
-    }
 }

common/transport/lwm2m/src/main/java/org/thingsboard/server/transport/lwm2m/server/rpc/DefaultLwM2MRpcRequestHandler.java

@@ -160,7 +160,6 @@ public class DefaultLwM2MRpcRequestHandler implements LwM2MRpcRequestHandler {
                         throw new IllegalArgumentException("Unsupported operation: " + operationType.name());
                 }
             }
-            transportService.process(client.getSession(), rpcRequest, RpcStatus.SENT, TransportServiceCallback.EMPTY);
         } catch (IllegalArgumentException e) {
             this.sendErrorRpcResponse(sessionInfo, rpcRequest.getRequestId(), ResponseCode.BAD_REQUEST, e.getMessage());
         }

common/transport/lwm2m/src/main/java/org/thingsboard/server/transport/lwm2m/server/rpc/RpcDownlinkRequestCallbackProxy.java

@@ -43,6 +43,11 @@ public abstract class RpcDownlinkRequestCallbackProxy<R, T> implements DownlinkR
         this.callback = callback;
     }
 
+    @Override
+    public void onSent(R request) {
+        transportService.process(client.getSession(), this.request, RpcStatus.SENT, TransportServiceCallback.EMPTY);
+    }
+
     @Override
     public void onSuccess(R request, T response) {
         transportService.process(client.getSession(), this.request, RpcStatus.DELIVERED, TransportServiceCallback.EMPTY);