interface IBone20 {
	// called when minting many NFTs
	// updated_amount = (balanceOf(user) * base_rate * delta / 86400)
	function updateRewardOnMint(address _user) external;
	// called on transfer
	function updateReward(address _from, address _to) external;
	function getReward(address _to) external;
	function burn(address _from, uint256 _amount) external;
	function getTotalClaimable(address _user) external view returns(uint256);
}
function updateReward(address _from, address _to) external;
// called on transfer