fee

type Fee struct {
	// Gas coin.Coin `json:"gas"`  // ?????
	Fee   coin.Coin `json:"fee"`
	Payer sdk.Actor `json:"payer"` // the address who pays the fee
	Tx    sdk.Tx    `json:"tx"`
}

type SimpleFeeMiddleware struct {
	// the fee must be the same denomination and >= this amount
	// if the amount is 0, then the fee tx wrapper is optional
	MinFee coin.Coin
	// all fees go here, which could be a dump (Bank) or something reachable
	// by other app logic
	Collector sdk.Actor
	stack.PassInitState
	stack.PassInitValidate
}