examples/tcp/tcp_file_sender/meta/tcp_file_sender.cmx

{
    "program": {
        "binary": "bin/tcp_file_sender"
    },
    "sandbox": {
        "features": [
            "persistent-storage"
        ],
        "services": [
            "fuchsia.net.SocketProvider",
            "fuchsia.logger.LogSink"
        ]
    }
}