ChatViewHolder

open class ChatViewHolder : ViewHolder, OnClickListener

ViewHolder for Chat it holds reference to frequent update views and provides helper method to bind data information onto views

constructor method that initialised the view holder by keeping reference to most frequent update views

ChatViewHolder(itemView: View)

cbFav	CheckBox button that denote the another user involved is buddy of current user `var cbFav: CheckBox!`
imgPic	icon for chat, usually display other user's profile picture `var imgPic: ImageView!`
tvLastMsg	last message of the chat `var tvLastMsg: TextView!`
tvName	name of the chat, usually display name of another user involved in chat `var tvName: TextView!`
tvUpdateTime	formatted timestamp for chat's last update time `var tvUpdateTime: TextView!`

bind	helper method to bind `Chat` onto item view `open fun bind(chat: Chat!): Unit`
onClick	catch user click event, and update observer via `#listener` `open fun onClick(v: View!): Unit`