allow tcp request with no dest, auto query topic.

lichao

2021-06-04 903b27f875e5f2a872c1b309f354b18c0450f35a

 .vscode/launch.json

@@ -14,7 +14,7 @@
                "ApiTest"
            ],
            "stopAtEntry": false,
            "cwd": "${workspaceFolder}",
            "cwd": "${workspaceFolder}/debug",
            "environment": [],
            "externalConsole": false,
            "MIMode": "gdb",