Add a property for this client, which will be sent to server at the connection start.
@param key the value of property key @param value the value of property value @return a reference to this, so the API can be used fluently
See Implementation
Add a property for this client, which will be sent to server at the connection start.
@param key the value of property key @param value the value of property value @return a reference to this, so the API can be used fluently