client.go
func (c *Client) Userlist(channel string) ([]string, error) {
	c.channelUserlistMutex.RLock()
	defer c.channelUserlistMutex.RUnlock()
	usermap, ok := c.channelUserlist[channel]
	if !ok || usermap == nil {
		return nil, fmt.Errorf("Could not find userlist for channel '%s' in client", channel)
	}
	userlist := make([]string, len(usermap))

	i := 0
	for key := range usermap {
		userlist[i] = key
		i++
	}

	return userlist, nil
}
func (c *Client) Userlist(channel string) ([]string, error) {
	c.channelUserlistMutex.RLock()
	defer c.channelUserlistMutex.RUnlock()
	usermap, ok := c.channelUserlist[channel]
	if !ok || usermap == nil {
		return nil, fmt.Errorf("Could not find userlist for channel '%s' in client", channel)
	}
	userlist := make([]string, len(usermap))

	i := 0
	for key := range usermap {
		userlist[i] = key
		i++
	}

	return userlist, nil
}
// Userlist returns the userlist for a given channel