func MapClientIp(req request.Request) (string, int64, error) {
	t, err := RequestToClientIp(req)
	return t, 1, err
}
MapClientIp creates a mapper that allows rate limiting of requests per client ip
package limit
import (
	"fmt"
	"github.com/mailgun/vulcan/middleware"
	"github.com/mailgun/vulcan/request"
	"strings"
)
type Limiter interface {
	middleware.Middleware
}
type MapperFn func(r request.Request) (token string, amount int64, err error)
type TokenMapperFn func(r request.Request) (token string, err error)
type AmountMapperFn func(r request.Request) (amount int64, err error)