gas

type Estimator interface {
	// EstimateGasPrice that should be used to get confirmation within a
	// reasonable amount of time. The precise definition of "reasonable amount
	// of time" varies from chain to chain, and so is left open to
	// interpretation by the implementation. For example, in Bitcoin, it would
	// be the recommended SATs-per-byte required to get a transaction into the
	// next block. In Ethereum, it would be the recommended GWEI-per-gas
	// required to get a transaction into one of the next few blocks (because
	// blocks happen a lot faster).
	EstimateGasPrice(context.Context) (pack.U256, pack.U256, error)
}