Replace the std client with gnet client in custom_codec example

[wathenjiang]

As Gnet client is now available for production, we could use client in gnet instead.

But I'm not 100% sure I use client.go correctly, please let me know if there are any mistakes.

[panjf2000]

You provide nothing here and expect me to pick up mistakes?

[wathenjiang]

You provide nothing here and expect me to pick up mistakes?

I means you uesed smallnest/goframe to implement a tcp client, but now cloud use client in gnet.

You not yet provided a quite simple client example in gnet.

[panjf2000]

Oh sorry, this is a PR, I thought it's an issue.

[panjf2000]

Have you tested your new code? Did it work? @Spongecaptain

[wathenjiang]

@panjf2000 I have tested it and it worked well. Turning smallnest/goframe to client.go in gnet just a little bit amendment.

You can find commands by:

• https://github.com/Spongecaptain/gnet-examples/blob/master/examples/codec/client/client.go#L26
• https://github.com/Spongecaptain/gnet-examples/blob/master/examples/codec/server/server.go#L58

&&

• https://github.com/Spongecaptain/gnet-examples/blob/master/examples/custom_codec/client/client.go#L33
• https://github.com/Spongecaptain/gnet-examples/blob/master/examples/custom_codec/server/server.go#L60

[panjf2000]

Why is go.mod changed so much？ did you run go mod tidy before opening this PR? @Spongecaptain

[wathenjiang]

Why is go.mod changed so much？ did you run go mod tidy before opening this PR? @Spongecaptain

I did run the go mod tidy.

[panjf2000]

Thanks~