func BodyLimit(limit string) echo.MiddlewareFunc {
	c := DefaultBodyLimitConfig
	c.Limit = limit
	return BodyLimitWithConfig(c)
}
BodyLimit returns a BodyLimit middleware.

BodyLimit middleware sets the maximum allowed size for a request body, if the
size exceeds the configured limit, it sends "413 - Request Entity Too Large"
response. The BodyLimit is determined based on both `Content-Length` request
header and actual content read, which makes it super secure.
Limit can be specified as `4x` or `4xB`, where x is one of the multiple from K, M,
G, T or P.
package middleware
import (
	"fmt"
	"io"
	"sync"
	"github.com/labstack/echo"
	"github.com/labstack/gommon/bytes"
)
type (
	BodyLimitConfig struct {
		Skipper Skipper
		Limit string `json:"limit"`
		limit int64
	}
	limitedReader struct {
		BodyLimitConfig
		reader  io.ReadCloser
		read    int64
		context echo.Context
	}
)
var (
	DefaultBodyLimitConfig = BodyLimitConfig{
		Skipper: DefaultSkipper,
	}
)