Add a way to derive Clone for the generated Request and Response types about tarpc

[tikue]

Thanks for the suggestion! I agree this could be supported.

It'd be nice to replace the derive_serde arg with something generic enough to support this new use case. Maybe something like this would be possible:

#[tarpc::service(derive = [tarpc::serde::Serialize, tarpc::serde::Deserialize, Clone, Hash])]
service World {
    async fn hello(message: String) -> String;
}

[ShaneMurphy2]

@tikue Got a first cut up on a branch: https://github.com/ShaneMurphy2/tarpc/tree/customizable-derives, let me know what you think so far.

Still need to see what breaks by changing the macro syntax, but the core use case works.

[tikue]

Looks nice! It'd be nice for derive_serde and derive to be mutually exclusive, so that people are encouraged to make the switch. In particular:

• derive_serde and derive at the same time should be an error
• derive should only derive Serialize/Deserialize when they are explicitly listed
• derive_serde is deprecated - output a warning when it is used, and suggest instead using either derive = [] to disable, or derive = [Serialize, Deserialize] to explicitly enable
• for backwards compatibility, absence of derive can derive Serialize/Deserialize by default.

[ShaneMurphy2]

Looks nice! It'd be nice for derive_serde and derive to be mutually exclusive, so that people are encouraged to make the switch. In particular:

• derive_serde and derive at the same time should be an error
• derive should only derive Serialize/Deserialize when they are explicitly listed
• derive_serde is deprecated - output a warning when it is used, and suggest instead using either derive = [] to disable, or derive = [Serialize, Deserialize] to explicitly enable
• for backwards compatibility, absence of derive can derive Serialize/Deserialize by default.

On it 👍

[ShaneMurphy2]

@tikue PR is up!