Const
Ref: https://github.com/paritytech/polkadot-sdk/blob/6a29a70a927de1017b5c54626c88c3fa439aef48/substrate/frame/system/rpc/runtime-api/src/lib.rs#L26-L35
Ref: https://github.com/paritytech/polkadot-sdk/blob/6a29a70a927de1017b5c54626c88c3fa439aef48/substrate/frame/system/rpc/runtime-api/src/lib.rs#L26-L35