Describe the feature request
In frps we can specify ports for tcp, kcp and quic, however in frpc.toml we only get to specify a single transport.protocol and serverPort.
It would be nice to be able to specify a comma-separated order of preferred protocols (and corresponding serverPort), that frpc would attempt.
Justification for this is the frpc that UDP protocols may be preferred, however firewalls may not always allow UDP, so a tcp fallback configuration would be nice.
Describe alternatives you've considered
Running multiple frpc daemons with different configs.
Affected area