func containsVWAPHeightOffsetError(err error) bool {
	if err == nil {
		return false
	}
	return strings.Contains(err.Error(), vwapHeightOffsetErrStr)
}
containsVWAPHeightOffsetError specifies whether or not the error
matches the error returned when the chain has not yet sufficiently
synced to the chain tip.
package ticketbuyer
import (
	"strings"
	"time"
	"github.com/HcashOrg/hcashutil"
)
var (
	vwapReqTries = 20
	vwapReqTryDelay = time.Millisecond * 500
)
type avgPriceMode int
const (
	AvgPriceVWAPMode = iota
	AvgPricePoolMode
	AvgPriceDualMode
)
var vwapHeightOffsetErrStr = "beyond blockchain tip height"