func (c *Client) SetTimeout(timeout time.Duration) {
	if timeout == time.Duration(0) {
		timeout = DefaultTimeout
	}
	c.timeout = timeout
}
func (c *Client) SetTimeout(timeout time.Duration) {
	if timeout == time.Duration(0) {
		timeout = DefaultTimeout
	}
	c.timeout = timeout
}
// SetTimeout specifies the socket read/write timeout.
// If zero, DefaultTimeout is used. If < 0, there's
// no timeout. This method must be called before any
// connections to the memcached server are opened.