Function spl_stake_pool::instruction::add_validator_to_pool_with_vote

pub fn add_validator_to_pool_with_vote(
    program_id: &Pubkey,
    stake_pool: &StakePool,
    stake_pool_address: &Pubkey,
    vote_account_address: &Pubkey,
    seed: Option<NonZeroU32>
) -> Instruction

Create an AddValidatorToPool instruction given an existing stake pool and vote account