username is the Symphony username of the person with whom the user wants to start/continue a 1-1 chat.
name is an optional parameter used to specify the first and last name of the person with whom the user wants to start/continue a 1-1 chat. This will be used for a fallback option if no user could be found with the provided username.
When the app is launched with the above URL, the UI should pop to the root view controller (if necessary) and then automatically dive into a 1-1 chat with John Smith.
If there was an existing 1-1 with the user john.smith, all the conversation history would be expected to be present.
If there was no existing 1-1 conversation with the user john.smith, a new 1-1 conversation would be created.
If there was no such user with the username john.smith, the user should be directed to a Global Search on the People tab with the search text field pre-populated with the user's full name.