Postgrest can be Clone

[jnhyatt]

Feature request

Hi!

Is your feature request related to a problem? Please describe.

I would like to be able to pass my Postgrest around my program to be able to make requests from multiple places, notably from async tasks I spawn periodically. My approach would be:

let client = postgrest.clone();
let task = task_pool.spawn(async move {
    let result = build_query(client).execute().await;
    handle_result(result).await
});

Describe alternatives you've considered

Leave as is and require the user to either:

• Create a new Postgrest at each call site. The downside to this would be that all information needed to build the client must be available as well. This breaks encapsulation as it requires users to "ship" state (access tokens, etc.) around instead of the Postgrest object, which could just do this for you.
• Use Rc or similar to share the Postgrest object throughout the program. This feels redundant as Client already stores an Arc to all the persistent, non-Clone state.

Additional context

Two facts jump out at me when looking at the implementation:

• Client is Clone (as are all other fields)
• Constructing a Postgrest is a simple matter -- very little state is stored in the structure
  Both of these hint to me that cloning should probably be a feature of the public API: if Postgrest only represents the state necessary to make a request, that state should probably be cloneable as it behaves similarly to POD.

Let me know what you think!

[soedirgo]

Thanks @jnhyatt! Builder is already Clone, I think it's reasonable to make Postgrest Clone too.

[jnhyatt]

Awesome, I'll send up a PR. Thanks!