use subxt::{OnlineClient, PolkadotConfig};
#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
// Create a client to use:
let api = OnlineClient::<PolkadotConfig>::new().await?;
// A dynamic query to obtain some contant:
let constant_query = subxt::dynamic::constant("System", "BlockLength");
// Obtain the value:
let value = api.constants().at(&constant_query)?;
println!("Constant bytes: {:?}", value.encoded());
println!("Constant value: {}", value.to_value()?);
Ok(())
}