feat: add RFD describing proposed batched query feature

[j-lanson]

Resolves #502 .

[alilleybrinker]

Thanks for this! Two comments:

• On the SDK changes, I think it should be possible to still have a single query function which uses a new trait to permit calling it with some a singular &'static str and &[&'static str] (or anything that derefs to that).
• Could the submit chunking actually be split into a separate RFD? It can be a small one. I'd view this as an oversight in the original design, I just think putting it here may make it hard to find later.

[alilleybrinker]

(Sorry, forgot to give my comments as a review: see my comments above)

[j-lanson]

• On the SDK changes, I think it should be possible to still have a single query function which uses a new trait to permit calling it with some a singular &'static str and &[&'static str] (or anything that derefs to that).

Can you elaborate on this point? As I understand, you're suggesting not having an explicit batch_query() function. I think interpreting whether a user wants to batch or not dependent on the type of the passed variable is wrong, because there may be some query endpoints that still take a Vec of objects. query(Vec<Value>) means "send this as a single request to the endpoint", batch_query(Vec<Value>) means "I don't want to waste time sending hc core each value individually, but they each represent a different query to X plugin"

[alilleybrinker]

• On the SDK changes, I think it should be possible to still have a single query function which uses a new trait to permit calling it with some a singular &'static str and &[&'static str] (or anything that derefs to that).

Can you elaborate on this point? As I understand, you're suggesting not having an explicit batch_query() function. I think interpreting whether a user wants to batch or not dependent on the type of the passed variable is wrong, because there may be some query endpoints that still take a Vec of objects. query(Vec<Value>) means "send this as a single request to the endpoint", batch_query(Vec<Value>) means "I don't want to waste time sending hc core each value individually, but they each represent a different query to X plugin"

Ah, you're right. Another thought though has occurred to me. It may be useful to, in addition to a singular batch_query method, also expose a batch() method which returns a handle with its own query() method, with the handle being consumed and the query sent with a send() (or some similar name) final method.

[j-lanson]

I added to the proposed PluginEngine interface changes to include the batch() function, and split the Submit chunking proposal into its own RFD

[alilleybrinker]

LGTM! 🎉