Const
Ref: https://github.com/paritytech/polkadot-sdk/blob/43415ef58c143b985e09015cd000dbd65f6d3997/substrate/primitives/session/src/runtime_api.rs#L21-L31
Ref: https://github.com/paritytech/polkadot-sdk/blob/43415ef58c143b985e09015cd000dbd65f6d3997/substrate/primitives/session/src/runtime_api.rs#L21-L31