code: func (c *Client) Channels(additionalQueries map[string]string) (*ChannelsList, error) {
  	path := fmt.Sprintf("/apps/%s/channels", c.AppId)
  	u, err := createRequestURL("GET", c.Host, path, c.Key, c.Secret, authTimestamp(), c.Secure, nil, additionalQueries, c.Cluster)
  	if err != nil {
  		return nil, err
  	}
  	response, err := c.request("GET", u, nil)
  	if err != nil {
  		return nil, err
  	}
  	return unmarshalledChannelsList(response)
  }
docs: /*
  One can use this method to get a list of all the channels in an application.
  
  The parameter `additionalQueries` is a map with query options. A key with `"filter_by_prefix"`
  will filter the returned channels. To get number of users subscribed to a presence-channel,
  specify an `"info"` key with value `"user_count"`. Pass in `nil` if you do not wish to specify any query attributes.
  
  	channelsParams := map[string]string{
  	    "filter_by_prefix": "presence-",
  	    "info":             "user_count",
  	}
  
  	channels, err := client.Channels(channelsParams)
  
  	//channels=> &{Channels:map[presence-chatroom:{UserCount:4} presence-notifications:{UserCount:31}  ]}
  
  */