func (e *element) UpdateLastAccessTime(now time.Time, expiration time.Duration) {
	e.expiration = now.Add(expiration)
}
UpdateLastAccessTime updates the expiration time of the element. This
should be called each time the element is accessed.
package common
import (
	"sync"
	"time"
)
type Key interface{}
type Value interface{}
type RemovalListener func(k Key, v Value)
type clock func() time.Time
type element struct {
	expiration time.Time
	timeout    time.Duration
	value      Value
}
func (e *element) IsExpired(now time.Time) bool {
	return now.After(e.expiration)
}