fixed double sending rpc (private network)

@@ -117,6 +117,10 @@ public class LwM2mClient implements Serializable {
     @Getter
     private final AtomicInteger retryAttempts;
 
+    @Getter
+    @Setter
+    private Integer lastSentRpcId;
+
     public Object clone() throws CloneNotSupportedException {
         return super.clone();
     }

@@ -95,6 +95,9 @@ public class DefaultLwM2MRpcRequestHandler implements LwM2MRpcRequestHandler {
             this.sendErrorRpcResponse(sessionInfo, rpcRequest.getRequestId(), ResponseCode.INTERNAL_SERVER_ERROR, "Registration is empty");
             return;
         }
+        if (client.getLastSentRpcId() != null && client.getLastSentRpcId().equals(rpcRequest.getRequestId())) {
+            log.info("[{}] Rpc has already sent!", rpcRequest.getRequestId());
+        }
         try {
             if (operationType.isHasObjectId()) {
                 String objectId = getIdFromParameters(client, rpcRequest);

@@ -45,6 +45,7 @@ public abstract class RpcDownlinkRequestCallbackProxy<R, T> implements DownlinkR
 
     @Override
     public void onSent(R request) {
+        client.setLastSentRpcId(this.request.getRequestId());
         transportService.process(client.getSession(), this.request, RpcStatus.SENT, TransportServiceCallback.EMPTY);
     }
 
@@ -68,6 +69,7 @@ public abstract class RpcDownlinkRequestCallbackProxy<R, T> implements DownlinkR
     @Override
     public void onError(String params, Exception e) {
         if (e instanceof TimeoutException || e instanceof org.eclipse.leshan.core.request.exception.TimeoutException) {
+            client.setLastSentRpcId(null);
             transportService.process(client.getSession(), this.request, RpcStatus.TIMEOUT, TransportServiceCallback.EMPTY);
         } else if (!(e instanceof ClientSleepingException)) {
             sendRpcReplyOnError(e);