Relay Example error

[xiaokugua250]

when i run relay example in https://github.com/libp2p/go-libp2p-examples/tree/master/relay i get two errors

1. h1, err := libp2p.New(context.Background(), libp2p.EnableRelay(circuit.OptDiscovery)) error is
   circuit.OptDiscovery is now a no-op: dialing peers with a random relay is no longer supported
2. relayaddr, err := ma.NewMultiaddr("/p2p-circuit/p2p/"+ h3.ID().Pretty()) report an't dial a p2p-circuit without specifying a relay: /p2p-circuit/p2p/QmPTjoYNMLSR8wzeRToMCwokMqCjz1TwBTdbJq7nX4TsWN
   

so how to use the libp2p-circuit ? or any other examples?
final i get these fixed by set
relayaddr, err := ma.NewMultiaddr("/p2p/"+h2.ID().Pretty()+"/p2p-circuit/p2p/"+ h3.ID().Pretty())

[xiaokugua250]

but when i write my own relay code and run it in 3 terminal i got error like this
length greater than remaining number of bytes in buffer
i dont know how to fix it ,
which raw code is in https://github.com/multiformats/multihash

[xiaokugua250]

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