examples/tcp/tcp_file_sender/meta/tcp_file_sender.cmx

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