What is the smartest way to make multiple dynamic storage queries using subxt?

Question

Is it possible to make batched storage calls to the runtime using subxt or is it only possible to make repeated individual calls against the state?

Say there are 3 storage variables I would like to query using subxt. I can do each of these individually:

let storage_addresses = vec![alice, bob, charlie]
    .iter()
    .map(|dest| subxt::dynamic::storage(
        "System",
        "Account",
        vec![
            // Something that encodes to an AccountId32 is what we need for the map key here:
            Value::from_bytes(&dest),
        ],
    )
);

let accounts = storage_addresses.iter().map(|a|
    api.storage()
        .fetch_or_default(&a, None)
        .await?
        .to_value()?
);

I'm curious if there is a smarter way to batch all these calls at once?

Answer 1

The options that I'm aware of are:

1. to do what you've done (whether you use static or dynamic storage lookups).
2. Use the "lower level" RPC method (api.rpc().query_storage_at(..) to query multiple entries at once (but you get bytes back and need to decode them manually), or
3. Use api.storage().iter(some_address) to iterate over all accounts (but you get nice types back here).