PoolMembers: StorageDescriptor<
    [Key: SS58String],
    {
        last_recorded_reward_counter: bigint;
        points: bigint;
        pool_id: number;
        unbonding_eras: [number, bigint][];
    },
    true,
    never,
>

Active members.

TWOX-NOTE: SAFE since AccountId is a secure hash.