func (c *Client) Notify(err error, sync bool, skip int) {
	if c.enable {
		c.notify(err, sync, skip)
	}
}
func (c *Client) Notify(err error, sync bool, skip int) {
	if c.enable {
		c.notify(err, sync, skip)
	}
}
// Notify takes three arguments:
// err - standard error;
// sync - if true then the function waits for the end of sending;
// skip - how many errors to remove from stacktrace.