A bonded member can use this to claim their payout based on the rewards that the pool
has accumulated since their last claimed payout (OR since joining if this is their first
time claiming rewards). The payout will be transferred to the member's account.
The member will earn rewards pro rata based on the members stake vs the sum of the
members in the pools stake. Rewards do not "expire".
See `claim_payout_other` to caim rewards on bahalf of some `other` pool member.
A bonded member can use this to claim their payout based on the rewards that the pool has accumulated since their last claimed payout (OR since joining if this is their first time claiming rewards). The payout will be transferred to the member's account.